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Preview: The night sky this month

The night sky this month



Ian Morison tells you what can be seen in the night sky this month.



Published: Fri, 15 Sep 2017 15:25:10 +0100

Copyright: Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 England & Wales Licence
 



The night sky for September 2017

Fri, 15 Sep 2017 15:30:00 +0100

The Night SkyNorthern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during September 2017.The PlanetsJupiter: Now five months after opposition, Jupiter can still just be seen very low in the southwestern sky after nightfall, lying at an elevation of some 10 degrees 45 minutes after sunset. By month's end it will be at an elevation of just 4 degrees at dusk. With a magnitude of -1.7 and an angular size of ~31 arc seconds it will be at its dimmest and smallest during this year's apparition and is too low for any reasonable telescopic views. At the start of September, Spica, Alpha Virginis, lies some 4 degrees to its lower left. Jupiter, moving eastwards passes 3 degrees to the upper right of Spica on September 11th. Now moving down towards the lower part of the ecliptic, next year it will only have an elevation of 25 degrees when due south whilst for the following two years an elevation of just 18 degrees.Saturn came into opposition back on June 11th and so will be seen in the southwest as darkness falls and sets late evening. It shines initially at magnitude +0.4 falling to +0.5 during the month and has an angular size of ~16.5 arc seconds. With an angle of 26.8 degrees inclination to the line of sight, the rings are virtually as open as they ever can be. Their maximum tilt, at 27 degrees, will come in October - the first time since 2002. It is sad that Saturn, now lying in the southern part of Ophiuchus between Sagittarius and Scorpius, only reached an elevation of ~17 degrees above the horizon when due south, so hindering our view of this most beautiful planet. If imaging Saturn (or Jupiter), Registax 6 has a tool to align the red, green and blue colour images to largely remove atmospheric dispersion from the image. At somewhat over £100 one can purchase the ZWO atmospheric dispersion corrector which uses two, contra rotating, prisms to carry out an even better correction - and which can also be used for visual observing.Mercury. has now become a morning object and will form a very tight grouping with Mars and Regulus, in Leo on the morning of the 5th. They will lie about 15 degrees below Venus. Binoculars will be needed to observe them in the bright twilight but please do not use them after the Sun has risen. Rising in elevation during the first part of the month, by the 10th it will have brightened to zero magnitude and lie just half a degree to lower right of Regulus. Mercury reaches greatest elongation, some 18 degrees from the Sun on the 12th - its best morning apparition this year. On the 14th, it lies 11 degrees to the lower left of Venus whilst, before dawn on the 16th, it closes to just 0.3 degrees from Mars. In the final week of September, moving back towards the Sun, it will be lost in the Sun's glare. . Mars has now become a morning object at the start of its new apparition. Lying in Leo, and still not easily seen in the pre-dawn sky, it forms a tight grouping with Mercury and Regulus on the 5th some 15 degrees to the lower left of Venus. During the month, Mars has a magnitude of 1.8 and an angular size of just 3.6 arc seconds so no details will be seen on its salmon-pink surface. As the month progresses Mars rises higher in the sky before dawn and moves closer to Venus which is now moving back towards the SunVenus is visible in the east before dawn this month, rising around 2 hours before sunrise. Its magnitude remains at -3.9 during the month as its angular diameter shrinks from 12.4 to 11.2 arc seconds. However, at the same time, its illuminated phase increases from 84 percent to 91 percent - which explains why its magnitude does not change. Highlights of the MonthSeptember - Find the globular cluster in Hercules and spot the 'Double-double' in Lyra: There are two very nice objects to spot with binoculars in the south-eastern sky well after dark this month. Two thirds of the way up the right hand side of the 4 stars that make up the 'keystone' in the constellation Hercules is M13, the best globular cluster visible in the no[...]


Media Files:
http://www.jodcast.net/archive/201709/20170901-jodcast-nightsky.mp3




The night sky for August 2017

Fri, 11 Aug 2017 14:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during August 2017.The PlanetsJupiter Now four months after opposition, Jupiter can still be seen low in the southwestern sky after nightfall. It sets at about 1 am BST as July begin. As the month progresses its brightness falls from -1.9 to -1.7 magnitudes as its angular size falls from 34 to 32 arc seconds. It lies in Virgo, initially some 8 degrees to the west of Spica, reducing to 4 degrees as the month progresses and will pass Spica on September 11th on its journey towards the lower parts of the ecliptic. Next year it will only reach an elevation of some 25 degrees when due south and, in the following two years, just 18 degrees before it moves back towards the more northerly parts of the ecliptic. Even so, with a small telescope one should easily be able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Gallilean moons as they weave their way around it. Saturn came into opposition on June 11th and so will be at its highest elevation due south as darkness falls. It shines initially at magnitude +0.3 falling to +0.4 during the month and has an angular size of ~17 arc seconds. With an angle of 26.8 degrees inclination to the line of sight, the rings are virtually as open as they ever can be. Their maximum tilt, at 27 degrees, will come in October - the first time since 2002. Saturn ceases its westwards, retrograde, motion on August 25th. It is sad that Saturn, now lying in the southern part of Ophiuchus between Sagittarius and Scorpius, only reaches an elevation of ~17 degrees above the horizon when due south so hindering our view of this most beautiful planet. If imaging Saturn (or Jupiter), Registax 6 has a tool to align the red, green and blue colour images to largely remove atmospheric dispersion from the image. At somewhat over £100 one can purchase the ZWO atmospheric dispersion corrector which uses two, contra rotating, prisms to carry out an even better correction - and which can also be used for visual observing. Mercury Given a very low western horizon, Mercury, showing an 8 arc second disk and shining at magnitude +0.4 might just be seen after sunset at the beginning of August. Binoculars may well be needed but please do not use them until after the Sun has set. It passes between the Earth and the Sun (inferior conjunction) on August 26th. Mars passed behind the Sun in July, but will be hidden in the Sun's glare all month so cannot be observed. Venus is visible in the east before dawn this month, rising around 3 hours before sunrise. Its magnitude dims slightly during the month from -4 to -3.9 as its angular diameter shrinks from 14.5 to 12.5 arc seconds. However, at the same time, its illuminated phase increases from 74 to 83% which explains why the magnitude does not drop too much. Its elevation before sunrise is greatest on August 2nd when Venus lies close to the open cluster M35 in Gemini. Highlights of the MonthAugust - Find the globular cluster in Hercules and spot the 'Double-double' in Lyra. Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae, often called the double-double. With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star - hence the name! August - A good month to observe Neptune with a small telescope. Neptune comes into opposition - when it is nearest the Earth - on the 2nd of September, so will be well placed both this month and next. Its magnitude is +7.9 so Neptune, with a disk just 3.7 arc seconds across, is easily spotted in binoculars lying in the constellation Aquarius as shown on the chart. It rises to an elevation of ~27 degrees when due south. Given a telescope of 8 inches or greater aperture and a dark transparent night it should even be possible to spot its moon Triton. (This is my objective around the end of the month!) The Moon and Saturn - Late evening on th[...]


Media Files:
http://www.jodcast.net/archive/201708/20170801-jodcast-nightsky.mp3




The night sky for July 2017

Wed, 5 Jul 2017 19:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during July 2017.The PlanetsJupiter - Now three months after opposition, Jupiter still dominates the low southwestern sky after nightfall. It sets at about 1 am BST as July begins. As the month progresses its brightness falls from -2.0 to -1.9 magnitudes as its angular size falls from 37 to 34 arc seconds. It lies in Virgo some 10.5 degrees to the west of Spica, now moving eastwards again after its period of retrograde motion. It will pass Spica on September 11th on its journey towards the lower parts of the ecliptic. Next year it will only reach an elevation of some 25 degrees when due south and, in the following two years, just 18 degrees before it moves back towards the more northerly parts of the ecliptic. Even so, with a small telescope one should easily be able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Galilean moons as they weave their way around it. Saturn - Saturn came into opposition on June 11th and so will be at its highest elevation due south at around midnight BST as July begins but by ~10 pm BST at its end. It will be visible throughout most of the short night. It shines initially at magnitude 0.1 falling to +0.2 during the month and has an angular size of ~18 arc seconds. With an angle of 26.7 degrees inclination to the line of sight, the rings are virtually as open as they ever can be. It is sad that Saturn, now lying in the southern part of Ophiuchus between Sagittarius and Scorpius, only reaches an elevation of ~17 degrees above the horizon when due south so hindering our view of this most beautiful planet. If imaging Saturn (or Jupiter), Registax 6 has a tool to align the red, green and blue colour images to largely remove atmospheric dispersion from the image. At somewhat over 100 GBP one can purchase the ZWO atmospheric dispersion corrector which uses two, contra rotating, prisms to carry out an even better correction - and which can also be used for visual observing. Mercury - Mercury reaches greatest elongation east, some 27 degrees from the Sun, on July 30th. It can be seen low in the west-northwest around 30 minutes after sunset. Binoculars may well be needed but please do not use them until after the Sun has set. It fades slightly during the month from -1.0 to +0.4 magnitudes whilst its angular size increases from 5.3 to 7.8 arc seconds. No surface details will, of course, be seen. Mars - Mars is hidden in the Sun's glare all month so cannot be observed. Venus - Venus is visible in the east before dawn this month rising around 2.5 hours before sunrise increasing to 3 hours as the month progresses. It magnitude dims slightly during the month from -4.2 to -4.0 as its angular diameter shrinks from 18.2 to 14.6 arc seconds. However, at the same time, its illuminated phase increases from 63 to 74% which explains why the magnitude does not drop too much. Even though it will be moving back towards the Sun, as the angle of the ecliptic to the horizon increases at this time of the year, it elevation before sunrise will continue to increase until August. Venus passes the Pleiades Cluster on the 5th, the Hyades on the 13/14th and ends the month close to M35 in Gemini.HighlightsJune - The best month to observe Saturn - Saturn reached opposition on the 14th of June, so is now due south and highest in the sky in the late evening. It lies in the southern part of Ophiuchus some 16 degrees up and to the left of the orange star Antares in Scorpius. Held steady, binoculars should enable you to see Saturn's brightest moon, Titan, at magnitude 8.2. A small telescope will show the rings with magnifications of x25 or more and one of 6-8 inches aperture with a magnification of ~x200 coupled with a night of good 'seeing' (when the atmosphere is calm) will show Saturn and its beautiful ring system in its full glory.Due to the orientation of Saturn's rotation axis of 27 degrees with respect to the plane of the solar [...]


Media Files:
http://www.jodcast.net/archive/201707/20170701-jodcast-nightsky.mp3




The night sky for June 2017

Sat, 10 Jun 2017 20:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during June 2017.The PlanetsJupiter - Now two months after opposition, Jupiter still dominates the late evening sky shining in the south to southwest after nightfall. It sets about 3 am BST as June begins and by about 1 am at its end. As the month progresses its brightness falls from -2.3 to -2 .0 magnitudes as its angular size falls from 41 to 37 arc seconds. It lies in Virgo some 11 degrees to the west of Spica, Alpha Virginis, and halts its westwards retrograde motion on the 11th as it begins its initially slow eastwards march back towards Spica. It will pass Spica on September 11th on its journey towards the lower parts of the ecliptic. Next year it will only reach an elevation of some 25 degrees when due south and, in the following two years, just 18 degrees before it moves back towards the more northerly parts of the ecliptic. Even so, with a small telescope one should easily be able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Gallilean moons as they weave their way around it.Saturn - Saturn comes into opposition on June 11th and so, then, will be at its highest elevation due south at around 1 am BST and will be visible throughout the short night. It shines at magnitude 0.1 all month and has an angular size of 18.3 arc seconds. With an angle of 26.5 degrees inclination to the line of sight the rings are virtually as open as they ever can be. It is sad that Saturn, now lying in the southern part of Ophiuchus between Sagittarius and Scorpius, only reaches an elevation of ~17 degrees above the horizon when due south so hindering our view of this most beautiful planet. If imaging Saturn (or Jupiter), Registax 6 has a tool to align the red, green and blue colour images to largely remove atmospheric dispersion from the image. At somewhat over £100 one can purchase the ZWO atmospheric dispersion corrector which uses two, contra rotating, prisms to carry out an even better correction.Mercury - Mercury is lost in the glare of the Sun for most of the month before it makes a modest evening apparition in July. It might just be spotted with binoculars very low in the west after sunset at the very end of the month. But please do not use them until after the Sun has set.Mars - Following a two year long apparition, Mars finally slips into the Sun's glare in the first week of June when its salmon-pink disk might just be picked out in the west-northwest.Venus - Venus is visible in the east before dawn this month reaching its greatest elongation (46 degrees west of the Sun) on the 3rd of June. It magnitude dims slightly during the month from -4.5 to -4.2 as its angular diameter shrinks from ~24 to 18 arc seconds. However, at the same time, its phase increases from 48 to 62 percent which explains why the magnitude does not drop too much. Even though it will be moving back towards the Sun, as the angle of the ecliptic to the horizon increases at this time of the year, it elevation before sunrise will continue to increase until August.HighlightsEarly June - still worth viewing Jupiter. .The features seen in the Jovian atmosphere have been changing quite significantly over the last few years - for a while the South Equatorial Belt vanished completely) but has now returned to its normal wide state. June - The best month to observe Saturn. .The thing that makes Saturn stand out is, of course, its ring system. The two outermost rings, A and B, are separated by a gap called Cassini's Division which should be visible in a telescope of 4 or more inches aperture if seeing conditions are good. Lying within the B ring, but far less bright and difficult to spot, is the C or Crepe Ring. Due to the orientation of Saturn's rotation axis of 27 degrees with respect to the plane of the solar system, the orientation of the rings as seen by us changes as it orbits the Sun and twice each orbi[...]


Media Files:
http://www.jodcast.net/archive/201706/20170601-jodcast-nightsky.mp3




The night sky for May 2017

Sun, 14 May 2017 19:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during May 2017.The Stars and GalaxiesThe PlanetsJupiter came into opposition on April 7th so, this month, transits in the late evening and is visible rising in the east at dusk. It is moving in retrograde motion lying in Virgo initially some 9 degrees over to the right of its brightest star, Spica. This increases to ~11 degrees as May progresses. The size of Jupiter's disk decreases slightly from 43.5. to 40.8 arc seconds during May with its magnitude reducing very slightly from -2.4 to -2.3. With a small telescope one should be easily able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Galilean moons as they weave their way around it.Saturn rises around 11:30pm BST as may begins and will be highest in the pre-dawn sky at ~4am BST. By the end of May it will rise at ~9:30pm BST and transit at around 2am BST. Lying in the western part of Sagittarius, its diameter increases from 17.8 to 18.3 arc seconds during the month as it brightness increases slightly from magnitude +0.3 to +0.1. It will be high enough in the south-east in the hours before dawn to make out the beautiful ring system which, at over 26 degrees to the line of sight, are nearly as open as they ever become. If only it were higher in the ecliptic; its elevation this year never gets above ~18 degrees and so the atmosphere will hinder our view of this most beautiful planet. [Note: I have acquired a ZWO Atmospheric Dispersion Corrector which uses two contra-rotating prisms to combat the dispersion of the atmosphere at low elevations. If imaging Saturn (or Jupiter), Registax 6 has a tool to align the red, green and blue colour images to largely remove the dispersion from the image.]Mercury is lost in the glare of the Sun this month so cannot be observed.Mars lies in Taurus initially making a shallow triangle with Aldabaran to its lower left and the Pleiades cluster to its lower right. In early May, Mars has an elevation of ~11 degrees above the western horizon at sunset, but this reduces to ~5 degrees by month's end when Mars will be lost in the Sun's glare. It will then be lost from view all summer as it passes behind the Sun. By month's end it will lie some 6.5 degrees over to the left of Alnath, Beta Tauri. Its brightness falls slightly during the month from magnitude +1.6 to +1.7 whilst its angular diameter falls from 3.9 to 3.7 arc seconds. No details would be expected to be seen on its salmon-pink surface.Venus rises in the east in the morning twilight on the first of the month and then climbs a little higher each morning as May progresses. On May 1st, the disk, forming a crescent 38 arc seconds high, is just 27% lit shining with a magnitude of -4.7 - its maximum brightness. By the end of the month, Venus shines at magnitude -4.5 with its angular size reduced to 25 arc seconds and its illuminated fraction increased to 48%. It is then close to its greatest elongation from the Sun of 46 degrees which it will reach on June 3rd. But, due to the shallow angle that the ecliptic makes to the horizon at this time of the year, it will then only have an elevation of ~16 degrees at sunrise.HighlightsJupiterThis is a great month to observe Jupiter which came into opposition on April 7th so, during May, will be visible in the south during the evening. It is moving down the ecliptic and lies in Virgo. It now reaches an elevation of ~36 degrees when crossing the meridian. An interesting observation is that the Great Red Spot appears to be diminishing in size. At the beginning of the last century it spanned 40,000 km across but now appears to be only ~16,500 Km across - less than half the size. It used to be said that 3 Earths could fit within it, but now it is only one. The shrinking rate appears to be accelerating and observations indicate that it is now reducing in size b[...]


Media Files:
http://www.jodcast.net/archive/201705/20170501-jodcast-nightsky.mp3




The night sky for April 2017

Sat, 01 Apr 2017 01:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during April 2017.The Stars and GalaxiesConstellations and StarsOrion setting in the west, with upper part of Taurus and the Pleiades still visible. Also above Orion Gemini is visible with the stars Caster above and Pollux below. Also below Gemini is Procyon the only bright star in Canis Minor. Leo is visible in the south with a wonderful region called the Realm of the Galaxies just behind the tail. Between Leo's tail and the bright star Arcturus (in Bootes) is Virgo and Coma Berenices with many Messier objects in that region. High overhead is Ursa Major with the Plough. The central star of the handle, Mizar, is a double star (with Alcor) and observable in a telescope is faint red star up to the right of the pair.The PlanetsJupitercomes into opposition on April 7th, lying in Virgo initially some 6 degrees above its brightest star, Spica. Visible all night, It will be due south at an elevation of 34 degrees at around midnight UT. The size of Jupiter's disk decreases slightly from 44.2 to 43.6 arc seconds as February progresses with its magnitude reducing very slightly from -2.5 to -2.4. With a small telescope one should be easily able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Galilean moons as they weave their way around it.Saturnrises around midnight (UT) and will be highest in the pre-dawn sky. Lying in the western part of Sagittarius, its diameter increases from 17 to 18 arc seconds during the month as it brightness increases slightly from magnitude +0.4 to +0.3. It will be high enough in the south-east in the hours before dawn to make out the beautiful ring system which, at over 26 degrees to the line of sight, are nearly as open as they ever become. If only it were higher in the ecliptic; its elevation this year never gets above ~18 degrees and so the atmosphere will hinder our view of this most beautiful planet. [Note: I have just acquired a ZWO Atmospheric Dispersion Corrector which uses two contra-rotating prisms to combat the dispersion of the atmosphere at low elevations.] Mercury passed through superior conjunction on March 7th and, on April 1st, will lie ~14 degrees above the western horizon at nightfall when it is at its greatest elongation, some 19 degrees, from the Sun. Then at magnitude -0.2, it brightness drops to magnitude +3 by the 18th of the month as it falls back towards the Sun. Mercury passes through inferior conjunction on the 20th and will reappear in the predawn sky by the end of the month. With an angular size of to 7.5 arc seconds on the 1st, increasing to 11 arc seconds on the 18th, no details would be expected to be seen on its disk.Mars As April begins, Mars lies in Aries but moves into Taurus on the 12th of the month. In early April, Mars has an elevation of ~20 degrees above the western horizon at sunset, but this reduces to ~11 degrees by month's end. On the 16th, it lies 4 degrees below the Pleaides cluster and then passes between the Pleiades and Hyades clusters on the 25th when it lies some 9 degrees to the right of Aldebaran. Its brightness falls slightly during the month from magnitude +1.5 to +1.6 whilst its angular diameter falls from 4.2 to 3.9 arc seconds. No details would be expected to be seen on its salmon-pink surface.Venus rises in the east about an hour before sunrise on the first of the month and then climbs a little higher each morning as April progresses. On April 1st, the disk, forming a slender crescent nearly one arc minute tall, is just 2 percent lit shining with a magnitude of -4.2. By the end of the month, Venus has its maximum brightness of magnitude -4.7 with its angular size reduced to 39 arc seconds and its illuminated fraction increased to 26 percent. It will then have an elevation of ~13 degrees at sunrise. In daytime when still high in the sky it can be imaged in the infrar[...]


Media Files:
http://www.jodcast.net/archive/201704/20170401-jodcast-nightsky.mp3




The night sky for March 2017

Wed, 01 Mar 2017 10:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during March 2017.Highlights of the Month1st-4th March - after sunset: Three planets and (on the 1st) a very thin crescent Moon. On these nights, Venus is 12 degrees down to the lower right of Mars, both in the southwest, and between them lies Uranus. On the 1st of March, they will be joined by a very thin waxing crescent Moon.March 4th, following 10pm: The Full Moon occults Gamma Tauri in the Hyades cluster. During the late evening, the first quarter Moon will occult the star Gamma Tauri, which forms the peak of the triangular shaped Hyades Cluster. In North America, the Moon can be seen occulting Aldebaran.10th March - all evening: The Moon, two days before full, passes just below Regulus in Leo.March 15th - before dawn: The Moon lies close to Jupiter and Spica. Before dawn, Jupiter appears between the Moon to its upper left and Spica, Alpha Virginis, down to its lower left.March 20th - before dawn: Saturn near the third quarter Moon. Before dawn on the 20th and looking South, Saturn will be seen over to the right of the third quarter Moon.March 6th and 19th: The Alpine Valley. These are two good nights to observe an interesting feature on the Moon with a small telescope. Close to the limb is the Appenine mountain chain that marks the edge of Mare Imbrium. Towards the upper end is a cleft called the Alpine Valley. The dark crater Plato will also be visible nearby.The PlanetsJupiter, moving towards opposition on April 7th, lies in Virgo initially some 4 degrees above its brightest star, Spica. With a small telescope, it should be easy to see the equatorial bands in the atmosphere, sometimes the Great Red Spot, and up to four of the Gallilean moons.Saturn rises well after midnight and will be highest in the pre-dawn sky. It will be high enough to make out the beautiful ring system which, at over 26 degrees to the line of sight, are as open as they ever become. Its elevation this year never gets above 18 degrees, so the atmosphere will hinder our view of this planet.Mercury passes through superior conjunction on March 7th and becomes visible around the 15th in bright twilight just above the western horizon. On the 19th, on its way up, it passes Venus, on its way down, some 9 degrees to its right.At the beginning of March, Mars can be found in Pisces up and to the left of Venus. As the month progresses, Mars continues to move eastwards (moving into Aries on the 8th) whilst Venus falls back towards the western horizon.Venus starts the month dominating the western sky, shining virtually at its brightest with a magnitude -4.8. It lies due south in mid-afternoon and can even by seen with the unaided eye. After dark in a very dark location, it can even form shadows. On the 1st of February, it has its highest elevation at sunset during the month at ~30 degrees. But then, as the month progresses, it falls back towards the Sun and passes in front of it on the 25th. Very unusually, Venus is far enough north of the Sun that it will start rising before dawn on March 15th, some 10 days before inferior conjunction. Thus it could be seen both at nightfall and at dawn for a few days. Southern HemisphereClaire Bretherton from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during March 2017.As we approach the autumn equinox on the 20th of March, our evenings are quickly drawing in, we have more time to get outside observing our beautiful Southern skies. The Milky Way, or te Ika Roa arches high across the sky from north-northwest to south-southeast after dark.Canopus, the second brightest star in our night time sky, is just to the southwest of overhead. Canopus is circumpolar from our position here and is considered to be a tapu, or sacred to Maori. Around halfway from Canopus to the southwest horizon is Acherna[...]


Media Files:
http://www.jodcast.net/archive/201703/20170301-jodcast-nightsky.mp3




The night sky for February 2017

Sat, 11 Feb 2017 09:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during February 2017.The PlanetsJupiter lies in Virgo some 3 and a half degrees above its brightest star, Spica. At the start of February it rises in the east at ~00:30 but by month's end by ~22:45. It will be due south at an elevation of 34 degrees at ~06:00 at the start and at ~04:00 by the end of February. The size of Jupiter's disk increases slightly from 39 to 42 arc seconds as February progresses with its magnitude increasing very slightly from -2.1 to -2.3. On February 6th, Jupiter halts its eastwards movement across the heavens and begins to move westwards in retrograde motion for several months. With a small telescope one should be easily able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Galilean moons as they weave their way around it.Saturn is now a morning object, rising in the south-east at ~08:00 UT as the month begin but by about 06:30 UT at its end. Lying in the southern part of Ophiuchus, its diameter increases from 15.6 to 16.1 arc seconds during the month as it shines at magnitude +0.5. Towards the end of the month it will be high enough in the south-east before dawn to make out the beautiful ring system which, at over 26 degrees to the line of sight, are as open as they ever become. If only it were higher in the ecliptic; its elevation this year will never gets above ~18 degrees in elevation and so the atmosphere will hinder our view of this most beautiful planet. [Note: I have just acquired a ZWO Atmospheric Dispersion Corrector which uses two contra-rotating prisms to combat the dispersion of the atmosphere at low elevations.]Mercury lies low in the southeast just before dawn down to the lower left of Saturn. It brightens from -0.2 to -1.2 during the month. It will be best seen around mid-month but no details would be expected to be seen on its disk which spans around 5 arc seconds across.Mars is easy to find this month lying in Pisces up and to the left of Venus. They are closest on February 1st with a separation of 5.4 degrees. By month's end, as Mars continues to move eastwards and Venus begins to fall back towards the western horizon, their separation increases to just over 12 degrees. Its brightness falls slightly from magnitude +1.1 to +1.3 whilst its angular diameter falls from 5.1 to 4.6 arc seconds. No details would be expected to be seen on its salmon-pink surface.Venus is dominating the western sky this month shining virtually at its brightest with a magnitude -4.8. Its close proximity to a crescent Moon last month was given a lot of attention! It lies due south in mid-afternoon and can even by seen with the unaided eye. After dark in a very dark location it can even form shadows! On the 4th of February it reaches its highest elevation of 33 degrees at sunset. Its angular size increases from 31 to 46 arc seconds during the month but at the same time the phase reduces from 40 percent to 18 percent illuminated. These two effects compensate each other which is why the brightness stays so constant. In visible light no details are seen on its brilliant white surface but cloud details can be seen or imaged in the ultra-violet. In daytime when still high in the sky it can be imaged in the infrared as the blue light from the sky is filtered out. This month's astronomy digest article on imaging the Moon and planets in the infrared shows how Venus looked on the 5th of January 2017.Highlights31st January to 5th February - after sunset: Venus approaches within 6 degrees of Mars If clear on the evenings of the 31st of January to the 5th of February and looking southwest one could not fail to spot Venus. But, on these nights Venus comes to within 5 degrees 23 arc seconds of Mars lying up to its left. On the 31st of January and the 1st of February, they will be joine[...]


Media Files:
http://www.jodcast.net/archive/201702/20170201-jodcast-nightsky.mp3




The night sky for December 2016

Fri, 02 Dec 2016 11:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during December 2016.Venus below a thin crescent MoonAfter sunset on December 3rd, looking low towards the south-southwest, Venus shining at magnitude -4.2, will be seen, if clear, below a very thin crescent Moon. December 4th after sunset: Venus, Mars and a crescent MoonIf clear after sunset on the 4th, looking low towards the south-southwest it should be possible to see a thin crescent Moon to the upper left of Mars with Venus well down to its right. December 13 before dawn: The Moon Occults Aldebaran in the Hyades ClusterDuring the night of the 12th/13th December, the Full Moon will pass throught the Hyades Cluster and occult many of its stars. At around 6:15 UT on the 13th, it will occult -0.7 magnitude Aldabaran which lies between us and the cluster. This may be a grazing occultation from parts of the UK.December 14th and 15th after midnight: the Geminid Meteor ShowerThe early mornings of December 14th and 15th will give us the chance, if clear, of observing the peak of the Geminid meteor shower. Sadly, this is not a good a year as these nights are just after the Full Moon and the fainter meteors will not be seen. However, as I saw last year, the Geminids can often produce near-fireballs and so the shower is still well worth observing. An observing location well away from towns or cities will pay dividends. The relatively slow moving meteors arise from debris released from the asteroid 3200 Phaethon. This is unusual, as most meteor showers come from comets. The radiant - where the meteors appear to come from - is close to the bright star Castor in the constellation Gemini as shown on the chart. If it is clear it will be cold - so wrap up well, wear a woolly hat and have some hot drinks with you.December 22nd/23rd - late evenings: the Ursid Meteor ShowerThe late evenings of the 22nd and 23rd of December are when the Ursid meteor shower will be at its best - though the peak rate of ~10-15 meteors per hour is not that great. Pleasingly, the Moon will not affect our view during much of the night. The radiant lies close to the star Kochab in Ursa Minor (hence their name), so look northwards at a high elevation. Occasionally, there can be a far higher rate so its worth having a look should it be clear. December 30th/ 31st after sunset: Venus closes on MarsAfter sunset at the end of the month, Mars, in Aquarius will be seen to the upper right of Venus low in the south-southwest.December 6th and 20th: The Alpine Valley These are good nights to observe an interesting feature on the Moon if you have a small telescope. Close to the limb is the Appenine mountain chain that marks the edge of Mare Imbrium.Towards the upper end you should see the cleft across them called the Alpine valley. It is about 7 miles wide and 79 miles long. As shown in the image a thin rill runs along its length which is quite a challenge to observe.Over the next two nights following the 6th the dark crater Plato and the young crater Copernicus will come into view. This is a very interesting region of the Moon!Haritina Mogosanu from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during December 2016. We'll start our tour in Orion, sitting high in the east after dark. Orion lies along the celestial equator, and can be seen (at least partially) throughout the world. As he was invented in the Northern hemisphere, in New Zealand we see him upside down. Orion contains a number of interesting objects to observe with both binoculars or telescopes. If you look carefully you may see the middle star of Orion's sword has a fuzzy appearance. This is the Orion Nebula, which is a stellar nursery, a huge cloud of gas and dust in which new stars are being born. In the heart of the Orion nebula is a small group of [...]


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The night sky for November 2016

Fri, 04 Nov 2016 17:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during November 2016.The PlanetsJupiter is the only planet that can be seen in the pre-dawn sky this month rising some two and a half hours before the Sun at the start of November, but by around 2:20 UT (GMT) by the end of the month. On the first of November it will lie some 20 degrees above the south-eastern horizon an hour before sunrise and some 10 degrees higher by month's end. Though at its smallest and dimmest, it still has a magnitude of around -1.7 and shows a 32 arc second disk. It remains in Virgo throughout the month and initially lies just 2 degrees below Porrima, Gamma Virginis, and sinks slowly southwards until by month's end it lies half way between Porrima and Spica, Alpha Virginis. With a small telescope, early risers should be able to see the equatorial bands in the atmosphere and the four Gallilean moons as they weave their way around it.Saturn is still visible low in the southwest after sunset, but is only some 10 degrees above the horizon 45 minutes after sunset. However as the month progresses it will sink lower and become harder to see. It lies in the southern part of Ophiuchus some 7 degrees up and to the left of Antares in Scorpius. One could not hope for a sharp view (but I am going to try using an Atmospheric Dispersion Corrector to help) but its wide open ring system should be seen. Sadly Saturn is moving towards the southern part of the ecliptic so for quite a few years will only be seen at low elevationsMercury, shining at magnitude -0.5 and with a disk some 5 arcs seconds across becomes visible low in the southwest after sunset by the third week of November and slowly climbs higher in the sky until it reaches its furthest angular distance from the Sun in mid December. It might just be spotted close to Venus on the 23rd.Mars, moving quickly eastwards through eastern Sagittarius and Capricornus, dims from magnitude +0.4 to +0.6 during November. The red (actually salmon pink) planet can be seen low above the southern horizon throughout the month but, with a disk only about 7 arc seconds across, no surface features will be seen.Venus, in the west, sets some 2 hours after the Sun at the start of the month but an hour later by month's end as it begins to dominate the evening sky. Its brightness increases from -4.0 to -4.2 magnitudes during the month whilst the angular size of its gibbous disk increases from 14 to 17 arc seconds. As it does so its phase reduces from 78 to 70% which explains why the brightness changes so little. Venus is moving eastwards, leaving Ophiuchus on the 9th into Sagittarius where it passes over the Teapot and will be just 7.5 arc minutes below its 'lid' star, Lamda Sagittari (shining at magnitude 2.8) on the 17th.HighlightsNovember early mornings: November Meteors.In the hours before dawn, November gives us a chance to observe meteors from two showers. The first that it is thought might produce some bright events is the Northern Taurids shower which has a broad peak of around 10 days but normally gives relatively few meteors per hour. The peak is around the 10th of November and, pleasingly, the Moon is first quarter on the 7th so, in the first week of November will have set by midnight. The meteors arise from comet 2P/Encke. Its tail is especially rich in large particles and, this year, we may pass through a relatively rich band so it is possible that a number of fireballs might be observed!The better known November shower is the Leonids which peak on the night of the 17th/18th of the month. Sadly, the Moon will be just after full so will hinder our view. As one might expect, the shower's radiant lies within the sickle of Leo and meteors could be spotted from the 15th to the 20th of the month. The Leonids enter the atmosp[...]


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The night sky for October 2016

Thu, 13 Oct 2016 19:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the Northern hemisphere night sky during October 2016.Highlights of the MonthOctober - A good month to observe Uranus with a small telescope.Uranus comes into opposition - when it is nearest the Earth - on the night of the 15th of October, so will be seen well this month - particularly from around the beginning and end of the month when no moonlight will intrude. Its magnitude is +5.9 so Uranus should be easily spotted in binoculars lying in the southern part of Pisces to the east of the Circlet asterism and east-southeast of 4th magnitude stars Epsilon Piscium and Delta Piscium as shown on the chart. It rises to an elevation of ~45 degrees when due south. Given a telescope of 4 inches it should be possible to see that it has a disk (3.6 arc seconds across) which has a pale green-blue tint. With an 8 inch telescope and good seeing, perhaps using a green filter it may even be possible to see some detail in the planet's cloud features which appear to be more prominent than usual. That is an observing challenge! Four of its satellites, Arial(+14.4), Umbrial(+15), Titania (+13.9) and Oberon (+14.1) can also be seen given a night of good seeing and a telescope of 8 inches diameter or more.October 3rd - after sunset: Venus and a very thin crescent Moon As twilight fades on the 3rd of October and given clear skies and a very low horizon in the south-west you may be able to spot Venus lying down to the left of a very thin crescent Moon, just 6.7percent illuminated. This gives you a chance of observing 'earthshine', the 'dark' side of the Moon faintly illuminated by light reflected from the Earth.October 8th, - one hour after sunset: the first quarter Moon lies above Mars After sunset, looking south and given clear skies, the first quarter Moon will be visible lying up to the left of Mars shining at magnitude +0.15. Mars, in Sagittarius, is lying just to the left of the top star of the Teapot, Lambda Sagittarii. Observe the International Space StationUse the link below to find when the space station will be visible in the next few days. In general, the space station can be seen either in the hour or so before dawn or the hour or so after sunset - this is because it is dark and yet the Sun is not too far below the horizon so that it can light up the space station. As the orbit only just gets up the the latitude of the UK it will usually be seen to the south, and is only visible for a minute or so at each sighting. Note that as it is in low-earth orbit the sighting details vary quite considerably across the UK. The NASA website linked to below gives details for several cities in the UK and across the world.Find details of sighting possibilities from your location from the location index. See where the space station is now using the tracking page.The Planets JupiterJupiter having passed behind the Sun last month, will appear again low above the eastern horizon around the 8th of October. On the 11th, Jupiter at magnitude -1.7 lies close to Mercury but they will only be ~5 degrees above the horizon 30 minutes before sunrise. As the month progreses, Jupiter rises a little earlier so that by month's end and still at magnitude -1.7, it rises some two and a half hours before the Sun. A low eastern horizon and the use of binoculars may well be needed but please do not use them after the Sun has risen. As the Earth moves towards Jupiter, the size of Jupiter's disk increases slightly from 30.6 to 31.2 arc seconds so early risers at the end of the month should be able to observe the equatorial bands in the atmosphere and the four Gallilean moons as they weave their way around it. SaturnOn September 11th, Saturn, lying in Ophiuchus, was just 6 degrees above, and a little to the left, of Antares in Sc[...]


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The night sky for September 2016

Mon, 05 Sep 2016 12:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during September 2016.The StarsTo the south and moving westward as night progresses you may see the Summer Triangle: the bright stars Deneb (in Cygnus), Vega (in Lyra) and below them Altair (in Aquila). Towards the south later in the evening you may spot the great square of Pegasus - adjacent to Andromeda and M31, the Andromeda Nebula. To the north lies "w" shaped Cassiopeia and Perseus. Between the two, close to the Milky Way, try to spot the Perseus Double Cluster with a goods pair of binoculars. You might also spot M33 may also be visible on a transparent night with a good pair of binoculars.The PlanetsJupiter reached superior conjunction on August 26th, and now rises shortly before the sun. It will be best seen at month's end, 18 degrees above the northeast horizon at sunrise. With a disk increasing to 31 arcsecond disk, you should be able to see its equitorial bands and 4 Galilean moons.Saturn can be seen after sunset low in the southwest. It lies in eastern Libra, moving slowly away from the wide double star Alpha Librae as it shines with a magnitude of +0.6. One hour after sunset at the start of the month it will lie just 10 degrees above the horizon with a 16.4 arc second disk. By month's end it will only be a few degrees elevation at this time so early this month is really our last chance to observe it for a month or so as it passes behind the Sun. The ring system, now opened out to 24.3 degrees to the line of sight, should still be visible along with Titan, its largest satellite.Mercury can be seen just above the western horizon for the first few days of the month reaching greatest elongation from the Sun on the 4th of September shining at magnitude +0.1. It will be lost in the twilight by mid-month before it passes in front of the Sun (Inferior Conjunction) on the 30th.Mars is a pre-dawn object, and lies in Leo not far from Regulus, Alpha Leonis. On the 25th the salmon-pink planet will lie just 47 arc minutes from the blue star making a very nice colour contrast. Shining at magnitude +1.8 its disk is just 3.8 arc seconds across so no details will be seen of its surface. Seen best towards the end of the month, it will then rise around 3 hours before the Sun.Venus, rises in the east-northeast in the pre-dawn sky an hour and a half before the Sun at the start of September but this increases to four hour by month's end as Venus moves further away in angle from the Sun. Shining at a magnitude -4.8 during the third week of the month month it will show a thin crescent, 9% illuminated, 52 arc second disk as the month begins.The MoonOn September 4th and 21st you may spot The Alpine Valley, a cleft across the Appenine mountain chain. It is about 7 miles wide and 79 miles long and a thin rill runs along its length which is quite challenging to observe.HighlightsNeptune came into opposition on the 29th of August, so will be seen well this month. Its magnitude is +7.9 so Neptune is easily spotted in binoculars lying in the constellation Aquarius as shown on the chart. It rises to an elevation of ~27 degrees when due south. Given a telescope of 8 inches or greater aperture and a dark transparent night it should even be possible to spot its moon Triton. Look east before dawn on 5th September: the magnitude +0.9 star Aldebaran will be occulted by the bright limb of the Moon as it passes in front of the Hyades cluster at around 05:30 BST. Given a mount tracking Aldebaran with a telescope, you may see it reappear from behind the unlit lunar disk at 07:10 in the bright daylight sky. Be warned: the times will vary by a few minutes depending on where you live in the UK so be watching Aldebaran for perhaps 10 minutes before the two stated tim[...]


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The night sky for August 2016

Mon, 1 Aug 2016 10:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during August 2016.Highlights of the monthAugust - Find the globular cluster in Hercules and spot the "Double-double" in Lyra There are two very nice objects to spot with binoculars high in the sky after dark this month. Two thirds of the way up the right hand side of the 4 stars that make up the "keystone" in the constellation Hercules is M13, the best globular cluster visible in the northern sky. Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae often called the double-double. With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star - hence the name.August - A good month to observe Neptune with a small telescope.Neptune comes into opposition - when it is nearest the Earth - on the 2nd of September, so will be well placed both this month and next. Its magnitude is +7.9, so Neptune, with a disk just 3.7 arcseconds across, is easily spotted in binoculars lying in the constellation Aquarius, as shown on the chart. It rises to an elevation of ~27 degrees when due south. Given a telescope of 8 inches or greater aperture and a dark tranparent night it should even be possible to spot its moon Triton.August 1st after sunset: Jupiter, Mercury, Regulus and Venus form a line in the Western Sky.Given a clear sky and a very low western horizon you may be able to spot a line of Jupiter, Mercury and Venus along with Regulus in Leo. Binoculars may well be needed, but please do not use them until the Sun has set.August 5th after sunset: Jupiter and a thin waxing crescent MoonAs Jupiter slowly sinks into the Sun's glare, given clear skies and a low western horizon it should be possible to spot Jupiter up and to the left of a thin waxing crescent Moon.August 23rd - after sunset: Saturn and Mars lie above Antares in Scorpius Looking South-Southwest after sunset and given a low horizon in this direction you should be able to spot Saturn (+0.4) lying above Mars (-0.3) (both in Ophiuchus) close to Antares in Scorpius.August 27th - after sunset: Venus and Jupiter less than half a degree apart. Looking west after sunset and given a very low horizon in this direction, binoculars may help you spot Jupiter and Venus less than half a degree apart. But please do not use binocluars until after the Sun has set. August 11th and 25th: The Straight WallThe Straight Wall is best observed either 1 or 2 days after First Quarter (evening of the 11th August best) or a day or so before Third Quarter (evening of the 25th August best). To honest, it is not really a wall but a gentle scarp - as Sir Patrick Moore has said, "Neither is it a wall nor is it straight."Observe the International Space StationUse the link below to find when the space station will be visible in the next few days. In general, the space station can be seen either in the hour or so before dawn or the hour or so after sunset - this is because it is dark and yet the Sun is not too far below the horizon so that it can light up the space station. As the orbit only just gets up the the latitude of the UK it will usually be seen to the south, and is only visible for a minute or so at each sighting. Note that as it is in low-earth orbit the sighting details vary quite considerably across the UK. The NASA website linked to below gives details for several cities in the UK and across the world.Find details of sighting possibilities from your location from the location index. See where the space station is now using the tracking page.The Planets JupiterJupiter can be seen low above the western horizon after sunset but throughout the month is sinking slowly i[...]


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The night sky for July 2016

Sat, 9 Jul 2016 12:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during July 2016.Highlights of the monthJuly - Still worth observing SaturnSaturn reached opposition on the 3rd of June, so is now low (at an elevation of ~ 20 degrees) in the west-southwest as darkness falls lying just over 6 degrees above the orange-red star Antares in Scorpius.   Held steady, binoculars should enable you to see Saturn's brightest moon, Titan, at magnitude 8.2. A small telescope will show the rings with magnifications of x25 or more and one of 6-8 inches aperture with a magnification of ~x200 coupled with a night of good "seeing" (when the atmosphere is calm) will show Saturn and its beautiful ring system in its full glory.As Saturn rotates quickly with a day of just 10 and a half hours, its equator bulges slightly and so it appears a little "squashed". Like Jupiter, it does show belts but their colours are muted in comparison. July - Find the globular cluster in Hercules and spot the "Double-double" in Lyra There are two very nice objects to spot with binoculars high in the south-western sky well after dark this month. Two thirds of the way up the right hand side of the 4 stars that make up the "keystone" in the constellation Hercules is M13, the best globular cluster visible in the northern sky. Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae often called the double-double. With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star - hence the name! Early July around midnight: look north to spot Noctilucent clouds. Noctilucent clouds, also known as polar mesospheric clouds, are most commonly seen in the deep twilight towards the north from our latitude. They are the highest clouds in the atmosphere at heights of around 80 km or 50 miles. Normally too faint to be seen, they are visible when illuminated by sunlight from below the northern horizon whilst the lower parts of the atmosphere are in shadow. They are not fully understood and are increasing in frequency, brightness and extent; some think that this might be due to climate change! So on a clear dark night as light is draining from the north western sky long after sunset take a look towards the north and you might just spot them!July 1st, 1 hour after sunset: Saturn and Mars make a triangle with Antares Around one hour after sunset on July 1st, given a clear sky and low southern horizon, you should be able to spot Saturn, above, and Mars, over to the right, or Antares in Scorpius. July 8th, 1 hour after sunset: A Waning Crescent Moon near Jupiter Around one hour after sunset on July 8th, given a clear sky and low western horizon, you should be able to spot Jupiter, above and to the left of a thin crescent Moon. July 16th after sunset: Venus and Mercury half a degree apartJuly 29th before dawn: A thin waning crescent Moon close to Aldebaran and the Hyades Cluster.July 30th after sunset: Mercury very close to Regulus in Leo.July 13th and 26th: Two Great Lunar CratersTwo great Lunar Craters: Tycho and CopernicusThese are great nights to observe two of the greatest craters on the Moon, Tycho and Copernicus, as the terminator is nearby. Tycho is towards the bottom of Moon in a densely cratered area called the Southern Lunar Highlands. It is a relatively young crater which is about 108 million years old. It is interesting in that it is thought to have been formed by the impact of one of the remnents of an asteroid that gave rise to the asteroid Baptistina. Another asteroid originating from the same breakup may well have caused the Chicxulub crater 65 million years a[...]


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The night sky for June 2016

Fri, 10 Jun 2016 14:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during June 2016.Highlights of the monthJune 1st - 8th: Mars at its best for 11 years. Mars reaches opposition - that is when the Earth lies between the Sun and Mars and when it was be approximately due south at midnight (UT) or 1am (BST) - on the 22nd of May, so it will be visible for most of the hours of darkness. However, it was actually be closest to the Earth and so having its greatest angular size of 18.6 arc seconds some 8 days later on the 30th of May. The angular size at closest approach varies due to the ellipticity of the orbit of Mars (and to a far lesser extent to that of the Earth) and will reach 26 arc seconds during 25,695 AD. At closest approach in 2003, Mars reached an angular size of 25.1 arc seconds, its largest angular diameter for 60,000 years. In July 2018 it will reach 24.2 arcseconds across but for both this opposition and that in 2018, Mars will be very low in the ecliptic and hence at low elevation so that the atmosphere will limit our views of the red (actually salmon pink) planet. Happily, it will be higher in the sky at the opposition of 2020. To find what should be visible at any time, one can use the Sky &Telescope application.June - The best month to observe Saturn. Saturn reaches opposition on the 3rd of June, so is now due south and highest in the sky around midnight (UT) or 1am (BST).It lies in the southern part of Ophiuchus 7 degrees up and to the left of the orange star Antares in Scorpius.Held steady, binoculars should enable you to see Saturn's brightest moon, Titan, at magnitude 8.2. A small telescope will show the rings with magnifications of x25 or more and one of 6-8 inches aperture with a magnification of ~x200 coupled with a night of good 'seeing' (when the atmosphere is calm) will show Saturn and its beautiful ring system in its full glory.As Saturn rotates quickly with a day of just 10 and a half hours, its equator bulges slightly and so it appears a little 'squashed'. Like Jupiter, it does show belts but their colours are muted in comparison.The thing that makes Saturn stand out is, of course, its ring system. The two outermost rings, A and B, are separated by a gap called Cassini's Division which should be visible in a telescope of 4 or more inches aperture if seeing conditions are good. Lying within the B ring, but far less bright and difficult to spot, is the C or Crepe Ring.Due to the orientation of Saturn's rotation axis of 27 degrees with respect to the plane of the solar system, the orientation of the rings as seen by us changes as it orbits the Sun and twice each orbit they lie edge on to us and so can hardly be seen. This last happened in 2009 and they are now opening out, currently at an angle of 26 degrees to the line of sight. The rings will continue to open out until May 2017 and then narrow until March 2025 when they will appear edge-on again.June - Find the globular cluster in Hercules and spot the "Double-double" in Lyra There are two very nice objects to spot with binoculars in the eastern sky well after dark this month. Two thirds of the way up the right hand side of the 4 stars that make up the "keystone" in the constellation Hercules is M13, the best globular cluster visible in the northern sky. Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae often called the double-double. With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star - hence the name!June 3rd just before dawn: Mercury close to a very thin crescent Moon.Some 30 or so minutes [...]


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The night sky for May 2016

Sat, 07 May 2016 20:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during May 2016.Highlights of the monthMay 9th - the Transit of Mercury across the face of the SunOn May the 9th, we will, if clear in the UK, be able to witness the complete passage of Mercury's disc across the face of the Sun. The transit begins soon after 11 hours UT, the midpoint of the transit is at 14:58 UT and Mercury leaves the Sun's disk at 18:42 UT - a total time of 7 and a half hours. This is Mercury's first transit since 2006 and the next will occur on November 11th 2019 but will not be so easily visible from the UK. These are three of the 13 or 14 Mercury transits that occur each century.Mercury's black disk will appear only 10 arcseonds across so binoculars or a telescope will be needed to observe the transit. If direct viewing is to be made a suitable solar filter must be placed in front of the objective(s). Filters made using Baader Solar Film are probably best. Alternatively, an image of the Sun can be projected onto white card using a small telescope or half binocular. An all metal eyepiece is needed to prevent heat damage and it's probably best to limit the aperture to ~1 inch across using a cardboard mask. Always take very great care when viewing the Sun - it is the only astronomical object that can harm us!At first glance Mercury's disk might, at just 1/200th of the Suns width, appear as a sunspot, but it will be precisely round, be even darker, will lack a grey penumbra and - of course - it will be moving across the Sun' disk. It will be interesting to watch the ingress and exit of Mercury's disk taking 3 minutes and 12 seconds to do so. Let's hope for clear skies!May 22nd to June 8th: Mars at its best for 11 yearsMars reaches opposition - that is when the Earth lies between the Sun and Mars and when it will be approximatly due south at midnight (UT) or 1 am (BST) - on the 22nd of May, so it will be visible for most of the hours of darkness. However, it will actually be closest to the Earth and so have its greatest angular size of 18.6 arc seconds some 8 days later on the 30th of May. The angular size at closet approach varies due to the ellipticity of the orbit of Mars (and to a far lesser extent to that of the Earth)and will reach 26 arc seconds during 25,695 AD. At closest approach in 2003, Mars reached an angular size of 25.1 arc seconds, its largest angular diameter for 60,000 years. In July 2018 it will reach 24.2 arc seconds across but for both this opposition and that in 2018, Mars will be very low in the ecliptic and hence at low elevation so that the atmosphere will limit our views of the red (actually salmon pink) planet. Happily, it will be higher in the sky at the opposition of 2020.To find what should be visible at any time, one can use the Sky &Telescope application. May: Look for the Great Red Spot on Jupiter3rd - 00:225th - 21:5210th - 21:0112th - 22:3917th - 21:4819th - 23:2724th - 22:3629th - 21:4531st - 23:24 May 5th and 6th before dawn: The Eta Aquarid Meteor ShowerThe Eta Aquarids are one of the finest meteor showers that can be seen from the southern hemisphere, but, in the northern hemisphere, may be glimpsed in the pre-dawn sky in the south-east around 90 minutes before dawn. Pleasingly, this year the peak corresponds to new Moon so there will be no moonlight to hinder our view.May 7th - one hour before sunrise: Saturn, Mars and Antares Looking to the South-Southwest in the hours before sunrise, Saturn, above, and Mars, to the upper right, can be seen close to Antares in Scorpius.May 7th - after sunset: a very thin waxing crescent MoonIf clear at sunset, a[...]


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The night sky for April 2016

Fri, 01 Apr 2016 13:30:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during April 2016.Highlights of the monthApril - still a great month to view Jupiter.This is still a great month to observe Jupiter. It lies in the southern part of Leo, but still reaches an elevations of ~48 degrees when crossing the meridian during the evening. An interesting observation is that the Great Red Spot appears to be diminishing in size. At the beginning of the last century it spanned 40,000 km across but now appears to be only ~16,500 km across - less than half the size. It used to be said that 3 Earths could fit within it, but now it is only one. The shrinking rate appears to be accelerating and observations indicate that it is now reducing in size by ~580 miles per year. Will it eventually disappear?The features seen in the Jovian atmosphere have been changing quite significantly over the last few years - for a while the South Equatorial Belt vanished completely but has now returned to its normal wide state.April: Look for the Great Red Spot on JupiterThe list below gives some of the best evening times during April to observe the Great Red Spot which should then lie on the central meridian of the planet.1st - 23:474th - 21:166th - 22:549th - 20:2411th - 22:0213th - 23:4116th - 21:1018th - 22:4920th - 21:0321st - 20:1823rd - 21:5725th - 23:2530th - 22:44April 3rd - 22:00 BST: Ganymede emerges from Jupiter's shadowDuring the early evening, Jupiter will apear to have just 3 Gallilean satellites: Io and Callisto to its right and Europa to its left. Ganymede is hiding in Jupiter's shadow but will emerge just after 22:00 BST later in the evening.April 6th: just before dawn - the Moon occults VenusOn the 6th of the month, the Moon and Venus will lie close together low in the eastern sky before dawn. At 08:28 BST, as observed from the centre of the UK, Venus will disappear behind the disk of the very thin crescent Moon whose phase will be just 2%. This will be quite an observing challenge and will need binoculars or a small telesocpe to observe along with a good low eastern horizon. BUT BEWARE NOT TO OBSERVE CLOSE TO THE SUN! If possible stand in the shadow of a wall to the left of your position. Ideally, using an equatorial mount, locate the Moon when it rises at 06:20 BST and continue tracking as it approaches and then occults Venus. As seen from the centre of the UK, it will emerge around 20 minutes later as it briefly passes behind the Moon's northern dark limb. The occultation will not be visible from Scotland and, in the northern part of the UK, Venus will be seen to graze along the Moon's rough northern edge. Venus will take ~60 seconds to disappear and ~70 seconds to emerge. NOTE: to show the occultation graphically, I have had to remove the Sun's glare - this will be a very difficult observation. April 8th: 45 minutes after sunset - Mercury and a thin crescent MoonLooking west after sunset and as darkness falls, Mercury will be seen just 6 degrees to the right and slightly up from the a very thin waxing crescent Moon.April 16th - mid evening: A waxing Moon nears JupiterDuring the evening the Moon will be seen gradually nearing Jupiter, closing in to a separation of just over 4 degrees at 22:00 UT. April 21st all night: The Moon at apogeeOn the 21st the Moon, one day from full, reaches apogee, that is at its furthest distance from the Earth. So, on the following day, it will not appear as big - or as bright - as when the full Moon is at perigee, its closest approach to the Earth. Perhaps surprisingly, its angular diameter at apogee is 12% smaller tha[...]


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The night sky for March 2016

Mon, 21 Mar 2016 22:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during March 2016.Highlights March - A superb month to view JupiterThis is a superb month to observe Jupiter. It now lies in Leo and so is still reasonably high in the ecliptic and hence, when due south at an elevation of ~48 degrees. Sadly, this peak elevations is reducing at each apparition. The features seen in the Jovian atmosphere have been changing quite significantly over the last few years - for a while the South Equatorial Belt vanished completely (as seen in Damian's image) but has now returned to its normal wide state. March: Look for the Great Red Spot on Jupiter This list gives some of the best evening times during March to observe the Great Red Spot which should then lie on the central meridian of the planet. 1st23:104th20:396th22:1711th21:2413th23:0216th20:3118th22:0920th23:4723rd21:1725th22:5528th20:2430th22:02March 5th, before dawn: Saturn, Mars and Antares. Before dawn this morning, Saturn and Mars will be seen above the star Antares, in Scorpius. March 16th before dawn: Mars very close to Beta Scorpii. Before dawn on the 16th, Mars will be seen in very close proximity to the star Beta Scorpii - the topmost star in the scorpion's tail fan. March 16th - evening: the Moon occults the star 26 Geminorum. Shortly after 7 pm - the exact time depending on your location in the UK - the fifth magnitude star, 26 Geminorum, will be occulted by the dark side of the Moon appearing again around an hour or so later. It is quite interesting to see the star suddenly disappear from view! March 16th ~10 pm: Ganymede and Io transit Jupiter. Around 9 - 11 pm on the 16th, first Ganymede and then Io will be seen to transit Jupiter - with their shadows (which are more obvious) - trailing behind. March 20th: Jupiter and the Moon. On the night of the 20th March, the Moon will be nearing Jupiter - as seen in the image around 10 pm in the evening. March 16th and 29th: The Alpine ValleyThese are two good nights to observe an interesting feature on the Moon if you have a small telescope. Close to the limb is the Appenine mountain chain that marks the edge of Mare Imbrium. Towards the upper end you should see the cleft across them called the Alpine valley. It is about 7 miles wide and 79 miles long. As shown in the image is a thin rill runs along its length which is quite a challenge to observe. The dark crater Plato will also be visible nearby. You may also see the shadow cast by the mountain Mons Piton lying not far away in Mare Imbrium. This is a very interesting region of the Moon! M16, the Eagle nebula, imaged with the Faulkes Telescope This image was taken using the Faulkes Telescope North by Daniel Duggan - for some time a member of the Faulkes telescope team. It is a region of dust and gas where stars are now forming. The ultraviolet light from young blue stars is stripping the electrons from hydrogen atoms so this region contains ionized hydrogen and is called an HII region. As the electrons drop back down through the hydrogen energy levels as the atoms re-form, red light at the H alpha wavelength is emitted. This "true colour" image is composed of red, green and blue images along with a narrow band H alpha image. A Hubble image of the central region, called the "Pillars of Creation", has become quite famous but looks green/blue in colour. This is a false colour image where the H alpha image has been encoded as green! Observe the International Space StationUse the link below to find when the space station will be visible in the next few[...]


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The night sky for February 2016

Mon, 01 Feb 2016 22:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during February 2016.Highlights of the monthFebruary - a great month to view JupiterThis is a great month to observe Jupiter. It now lies low down in Leo and so is still reasonably high in the ecliptic and hence, when due south, at an elevation of ~45 degrees.The features seen in the Jovian atmosphere have been changing quite significantly over the last few years - for a while the South Equatorial Belt vanished completely, but has now returned to its normal wide state. This diagram shows the main Jovian features as imaged by the author at the beginning of December 2012.The image by Damian Peach was taken with a 14 inch telescope in Barbados where the seeing can be particularly good. This image won the Astronomy Photographer of the Year competition in 2011.February: Look for the Great Red Spot on Jupiter This list gives some of the best evening times during February to observe the Great Red Spot which should then lie on the central meridian of the planet. 2nd 20:11 4th 21:48 6th 23:36 7th 19:18 9th 20:56 11th 22:33 14th 20:02 16th 21:40 18th 23:18 21st 20:47 23rd 22:25 28th 21:32 1st February: before dawn: Mars and the third quarter Moon Before dawn on the first of the month, Mars and the third quarter Moon will be seen, if clear, due south. As it nears the Earth, some details on the surface may now be seen if the seeing is good. Antares, in Scorpius, may also be spotted low above the horizon. February 6th: just before dawn: A very thin crescent Moon above Venus and Mercury Just before dawn and, given clear skies and a very low horizon towards the south-east, you may be able to spot a very thin crescent Moon hanging above both Venus, below, and Mercury down to its lower left. Binoculars may well be needed to spot Mercury, but please do not use them after the Sun has risen. February 13th: Observe the Moon occult a star If clear, around 19:20 on the evening of the 13th, the Moon will be seen to occult the 4.4th magnitude star xi 1 Ceti. The chart show the position of the star as seen from Manchester just before it is occulted by the un-illuminated disk of the Moon. It will reappear below the Moon's illuminated disk at around 20:19. The timings will vary somewhat across the UK. February 14th: The Moon passes close to the Hyades ClusterA very nice visual or photo opportunity when the first quarter Moon passes close to the V-shaped Hyades Cluster. The red giant star, Aldebaran, shining at magnitude +0.8 is not part of the cluster but lies part way towards it.February 23rd: The Moon close to Jupiter On the night of the 23rd/24th of February, the near full Moon, will pass below Jupiter. The diagram shows the relative positions at ~21:30 in the evening and also the positions of the Gallilean satellites. February 26th evening: The Hyginus RilleFor some time a debate raged as to whether the craters on the Moon were caused by impacts or volcanic activity. We now know that virtually all were caused by impact, but it is thought that the Hyginus crater that lies at the centre of the Hyginus Rille may well be volcanic in origin. It is an 11 km wide rimless pit - in contast to impact craters which have raised rims - and its close association with the rille of the same name associates it with internal lunar events. It can quite easily be seen to be surrounded by dark material. It is thought that an explosive release of dust and gas created a vacant space below so tha[...]


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The night sky for January 2016

Sat, 09 Jan 2016 10:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during January 2016.The StarsIn the mid to late evening January sky the brilliant constellation of Orion may be seen in the south. Moving up and to the right - following the line of the three stars of Orion's belt - brings one to Taurus; the head of the bull being outlined by the V-shaped cluster called the Hyades with its eye delineated by the orange red star Aldebaran. Further up to the right lies the Pleiades Cluster. Towards the zenith from Taurus lies the constellation Auriga, whose brightest star Capella will be nearly overhead. To the upper left of Orion lie the heavenly twins, or Gemini, their heads indicated by the two bright stars Castor and Pollux. Down to the lower left of Orion lies the brightest star in the northern sky, Sirius, in the constellation Canis Major. Finally, up and to the left of Sirius is Procyon in Canis Minor.The Planets Jupiter, shining at magnitude -2.2, rises at around 20:30 UT at the beginning of the month lying low in south-eastern Leo. It begins its retrograde motion, moving westwards across the heavens, on January 8th. By the end of the month it rises at around 19:30 UT with a slight increase in magnitude to -2.4. It will then be due south and so highest in the sky at an elevation of 45 degrees around 01:30 UT. As the Earth moves towards Jupiter, the size of Jupiter's disk increases slightly from 39 to 42.4 arc seconds so one should be easily able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Galilean moons as they weave their way around it. Saturn is now a morning object, rising at 06:15 UT as the month begin but by about 04:30 UT at its end. It lies in the southern part of Ophiuchus some 7 degrees up and to the left Antares and close to the stars that mark the head of Scorpius. Its diameter increases from 15.3 to 15.8 arc seconds during the month with its ring system spanning some 35 arc seconds. It will be shining at magnitude +0.5 and be high enough in the south-east before dawn to make out the beautiful ring system which has now opened out to ~25 degrees. Mercury on New Year’s Day will shine at magnitude -0.4 about 7 degrees above the south-western horizon 30 minutes after sunset. Binoculars will be probably needed to spot it but please do not use them until after the Sun has set. Over the next week it falls back towards the horizon with a much reducing magnitude (down to +1.8) and will be increasingly difficult to spot. It passes through inferior conjunction with the Sun on January 14th and might be just possible to spot in the east before dawn at the end of the month shining at at magnitude 0.0. At its next inferior conjunction on May 9th it will be seen to transit across the face of the Sun, its first transit for 10 years.Mars, moving eastwards relative to the stars, starts the month in Virgo, 6 degrees from Spica, but moves into Libra mid month. Its brightness increases slightly from magnitude +1.3 to +0.8 during the month as the angular size of its disk increases from 5.6 to 6.8 arc seconds. Mars rises about 01:30 on New Year's Day and around half an hour earlier by month's end when it will lie just 1.3 degrees north of the double star Alpha Librae. Given really good seeing, some details on the surface such as Syrtis Major and the polar caps may be visible with a telescope, but will be far better seen at opposition in May when it will appear around three times wider. Venus rises around three hours [...]


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The night sky for December 2015

Tue, 08 Dec 2015 10:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during December 2015.Highlights of the monthDecember - the first good month to view JupiterThis is the first of several great months to observe Jupiter. It now lies low in Leo and so is still reasaonably high in the ecliptic and hence, when due south, at an elevation of ~45 degrees. It is looking somewhat different than in the last few years as the north equatorial belt has become quite broad. The Great Red Spot is currently a pale shade of pink but can be easily seen as a large feature (which appears to be shrinking in size) in the South Equatorial Belt.[...]


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The night sky for November 2015

Sun, 08 Nov 2015 14:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during November 2015.Highlights of the monthNovember early mornings - meteorsIn the hours before dawn, November gives us a chance to observe meteors from two showers - the Northern Taurids shower and the better known Leonids. The Northern Taurids shower has a broad peak of around 10 days but normally gives relatively few meteors per hour. The peak is around the 10th of November and, pleasingly, the Moon is new on the 11th. The meteors arise from comet 2P/Encke, which has a tail especially rich in large particles, so it is possible that a number of fireballs might be observed!The Leonids are also expected to produce bright events, peaking on the night of the 17th/18th of the month, with up to 15 meteors an hour visible to those near the zenith. The Moon sets at 21:30 on the 17th so will not be a problem when observing the first predicted peak at 21:00 UT on the 17th and the second at 04:00 on the 18th. As one might expect, the shower's radiant lies within the sickle of Leo and meteors could be spotted from the 15th to the 20th of the month. The Leonids enter the atmosphere at ~71 km/sec and this makes them somewhat challenging to photograph but it's worth trying as one might just capture a bright fireball. The Leonids are famous because every 33 years a meteor storm might be observed when the parent comet, 55P/Temple-Tuttle, passes close to the Sun. In 1999, 3,000 meteors were observed per hour but we are now halfway between these impressive events hence with a far lower expected rate.November 3rd - before sunrise: Venus and Mars under a degree apart.Before dawn on the 3rd, brilliant Venus shining at magnitude -4.5 will be very close to Mars at magnitude +1.7. Jupiter will lie ~7 degrees to their upper right.November 7th - before sunrise: A thin crescent Moon joins the morning planets.An excellent imaging opportunity arises before dawn on the 7th as a thin crescent Moon lies close to Venus and Mars with Jupiter some 9 degrees to their upper right.Find The Andromeda Galaxy (M31) around the second week of November - and for an extra challenge, perhaps M33 in TriangulumIn the evening, the galaxy M31 in Andromeda is visible in the south. The chart on the Jodrell Bank night sky page shows two ways of finding it:Find the square of Pegasus Start at the top left star of the square - Alpha Andromedae - and move two stars to the left and up a bit. Then turn 90 degrees to the right, move up to one reasonably bright star and continue a similar distance in the same direction. You should easily spot M31 with binoculars and, if there is a dark sky, you can even see it with your unaided eye. The photons that are falling on your retina left Andromeda well over two million years ago!You can also find M31 by following the "arrow" made by the three rightmost bright stars of Cassiopeia down to the lower right as shown on the chart.Around new Moon (11th November) - and away from towns and cities - you may also be able to spot M33, the third largest galaxy after M31 and our own galaxy in our Local Group of galaxies. It is a face on spiral and its surface brightness is pretty low so a dark, transparent sky will be needed to spot it using binoculars (8x40 or, preferably, 10x50). Follow the two stars back from M31 and continue in the same direction, sweeping slowly as you go. It looks like a piece of tissue paper stuck on the sky, just slightly brighter than the sky background. Happ[...]


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The night sky for October 2015

Tue, 06 Oct 2015 15:45:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during October 2015.The StarsTo the south in early evening - moving over to the west as the night progresses is the beautiful region of the Milky Way containing both Cygnus and Lyra. Below is Aquilla. The three bright stars Deneb (in Cygnus), Vega (in Lyra) and Altair (in Aquila) make up the "Summer Triangle". East of Cygnus is the great square of Pegasus - adjacent to Andromeda in which lies M31, the Andromeda Nebula. To the north lies "w" shaped Cassiopeia with Perseus below.The Square of Pegasus is in the south during the evening and forms the body of the winged horse. The square is marked by 4 stars of 2nd and 3rd magnitude, with the top left hand one actually forming part of the constellation Andromeda. The sides of the square are almost 15 degrees across, about the width of a clentched fist, but it contains few stars visibe to the naked eye. If you can see 5 then you know that the sky is both dark and transparent! Three stars drop down to the right of the bottom right hand corner of the square marked by Alpha Pegasi, Markab. A brighter star Epsilon Pegasi is then a little up to the right, at 2nd magnitude the brightest star in this part of the sky. A little further up and to the right is the Globular Cluster M15. It is just too faint to be seen with the naked eye, but binoculars show it clearly as a fuzzy patch of light just to the right of a 6th magnitude star.The PlanetsJupiter is one of the pre-dawn planets that we can observe this month. Shining at magnitude -1.7 (increasing to -1.8 during the month) it starts the month as the lowest of the pre-dawn planets and will be just 12 degrees above the eastern horizon as dawn breaks. It rises earlier as the month progresses moving upwards towards Regulus under the body of Leo, the lion, and will meet with Mars on the 17th of the month. As the Earth moves towards Jupiter, the size of Jupiter's disk increases slightly from 31.4 to 33 arc seconds so early risers should be able to easily observe the equatorial bands in the atmosphere and the four Gallilean moons as they weave their way around it.Saturn may be seen at the start of October, shining at magnitude +0.6 at an elevation of ~7 degrees low in the southwest about 45 minutes after sunset. As the month progresses it will become increasingly hard to spot in the evening twilight. It starts the month in eastern Libra setting around 2 hours after the Sun but passes into Scorpius on the 16th and is less than one degree above Beta Scorpii on the 26th of the month. By month's end it sets one hour after the Sun. Sadly, the atmosphere will seriously limit our view of its ~15 arc second disk and rings - now open ~24 degrees to the line of sight. We will have to wait for a few months until it can be seen in the pre-dawn sky.Mercury is also a pre-dawn object this month becoming visible (at magnitude +0.3) about the 11th close to a thin crescent Moon - but just 8 degrees above the horizon some 40 minutes before sunrise. Binoculars may well be needed to spot it. At this time Mercury will lie 20 degrees below Jupiter. Mercury reaches greatest elongation west on the 16th but falls back towards the Sun brightening to magnitude -1 as it does so but becoming increasingly difficult to spot.Mars is also a pre-dawn object starting the month almost halfway between Venus (above) and Jupiter (below) shining at magnitude +1.8 some 23 degrees above the eastern[...]


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The night sky for September 2015

Fri, 04 Sep 2015 12:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during September 2015.The StarsTo the south and moving westward as night progresses you may see the Summer Triangle: the bright stars Deneb (in Cygnus), Vega (in Lyra) and below them Altair (in Aquila). Towards the south later in the evening you may spot the great square of Pegasus - adjacent to Andromeda and M31, the Andromeda Nebula. To the north lies "w" shaped Cassiopeia and Perseus. Between the two, close to the Milky Way, try to spot the Perseus Double Cluster with a goods pair of binoculars. You might also spot M33 may also be visible on a transparent night with a good pair of binoculars.The PlanetsJupiter reached superior conjunction on August 26th, and now rises shortly before the sun. It will be best seen at month's end, 18 degrees above the northeast horizon at sunrise. With a disk increasing to 31 arcsecond disk, you should be able to see its equitorial bands and 4 Galilean moons.Saturn can be seen after sunset low in the southwest. It lies in eastern Libra, moving slowly away from the wide double star Alpha Librae as it shines with a magnitude of +0.6. One hour after sunset at the start of the month it will lie just 10 degrees above the horizon with a 16.4 arc second disk. By month's end it will only be a few degrees elevation at this time so early this month is really our last chance to observe it for a month or so as it passes behind the Sun. The ring system, now opened out to 24.3 degrees to the line of sight, should still be visible along with Titan, its largest satellite.Mercury can be seen just above the western horizon for the first few days of the month reaching greatest elongation from the Sun on the 4th of September shining at magnitude +0.1. It will be lost in the twilight by mid-month before it passes in front of the Sun (Inferior Conjunction) on the 30th.Mars is a pre-dawn object, and lies in Leo not far from Regulus, Alpha Leonis. On the 25th the salmon-pink planet will lie just 47 arc minutes from the blue star making a very nice colour contrast. Shining at magnitude +1.8 its disk is just 3.8 arc seconds across so no details will be seen of its surface. Seen best towards the end of the month, it will then rise around 3 hours before the Sun.Venus, rises in the east-northeast in the pre-dawn sky an hour and a half before the Sun at the start of September but this increases to four hour by month's end as Venus moves further away in angle from the Sun. Shining at a magnitude -4.8 during the third week of the month month it will show a thin crescent, 9% illuminated, 52 arc second disk as the month begins.The MoonOn September 4th and 21st you may spot The Alpine Valley, a cleft across the Appenine mountain chain. It is about 7 miles wide and 79 miles long and a thin rill runs along its length which is quite challenging to observe.HighlightsNeptune came into opposition on the 29th of August, so will be seen well this month. Its magnitude is +7.9 so Neptune is easily spotted in binoculars lying in the constellation Aquarius as shown on the chart. It rises to an elevation of ~27 degrees when due south. Given a telescope of 8 inches or greater aperture and a dark transparent night it should even be possible to spot its moon Triton. Look east before dawn on 5th September: the magnitude +0.9 star Aldebaran will be occulted by the bright limb of the Moon as it passes in front of the Hyades clust[...]


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The night sky for August 2015

Mon, 03 Aug 2015 09:00:00 +0000

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during August 2015.Southern HemisphereClaire Bretherton from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during August 2015.The PlanetsAt the beginning of the month three bright planets appear low in the western evening sky soon after Sunset. Brilliant silvery Venus is the brightest and highest with golden Jupiter below and right. Mercury is well below the two bright planets on August 1st, but moves quickly up the sky, night to night, as Venus and Jupiter sink lower. On the 7th Mercury is just a full-moon's diameter to the right of Jupiter. Venus is left of the close pair of planets, and all three set about 70 minutes after the Sun.After passing between us and the Sun mid-month, Venus will appear in the eastern dawn twilight. By August 20th it will be rising in the east an hour before the Sun. Venus will remain the 'morning star' for the rest of the year.Mercury continues its ascent of the evening sky through August while Venus and Jupiter disappear in the twilight. By month's end Mercury is setting due west after 8 pm, making its best evening sky appearance of the year. The bright orange star Arcturus is setting in the northwest, well to the right of Mercury, often flashing red and green as it goes.Saturn is the only bright planet in the late-evening sky. A small telescope shows Saturn's ring system and biggest moon, Titan, looking like a star about four ring-diameters from the planet. More powerful telescopes should reveal faint banding in the planets atmosphere along with gaps and variation in colour of the rings.The StarsIn the north, to the left side of the Milky Way is Vega, the fifth brightest star in the sky, which forms part of the constellation of Lyra that represents an ancient stringed instrument. Opposite Vega, in the south, Canopus is the second brightest star in the night sky and twinkles with a yellow tint. To the Polynesians this star is Atutahi, the navigator, considered by Māori as the chief of all the stars in the sky. Canopus was also the navigator of Argo Navis, the ship in which the argonauts searched for the Golden Fleece. Argo Navis, once the biggest constellation in the sky, was subdivided into Carina (the keel, or the hull, of the ship), Puppis (the poop deck, or stern), and Vela (the sails). These constellations now hold the asterisms known as the false and diamond crosses which are adjacent to Crux, the Southern Cross.Above Crux are Alpha Centauri, the third brightest star, and Beta Centauri, the 11th brightest star in our night sky, which point you towards the Southern Cross and appear to follow it around the sky. To the north of Beta Centuri lies the brightest globular cluster, Omega Centuri, which can be seen as a fuzzy star. With a small telescope the cluster becomes a glowing, shimmering ball of stars, with many individual stars visible towards the outskirts of the cluster.Sitting about half way above the southern horizon as the Southern Cross sinks towards its lowest position in the sky is the faint constellation of Tucana, the Toucan. Alpha Tucanae is a magnitude +2.8 star about 200 light years away. Beta Tucanae is a loose group of 6 gravitationally bound stars approximately 140 light years away. The two exceptional objects in the Toucan are the Small Magellanic Cloud (SMC) and 47 Tucanae the second b[...]


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The night sky for July 2015

Mon, 06 Jul 2015 17:00:00 +0000

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during June 2015.Arcturis, the brightest star in the constellation of Bootes, is visible in the southwest. Meanwhile, in the northwest, Merak and Dubhe of the constellation Ursa Major may be seen pointing towards the Polaris near the North Celestial Pole. Further north the w-shaped set of stars which form Cassiopeia may be seen, while towards the east the Summer Triangle is clearly visible. It is composed of three bright stars: Vega of Lyra, Deneb of Cygnus, and Altair of Aquila. Just to the left of Vega lies the Double-double: what appears to be a binary star system when viewed with binoculars becomes two binaries when observed through a telescope. Below Albireo, the head of Cygnus the Swan, the Cygnus Rift, a dark, dusty region of the Milky Way may be seen. Within the Cygnus Rift you may spot Brocchi's Cluster, also known as the Coathanger, while to the lower left of the summer triangle lies a faint constellation known as Delphinus the dolphin. Halfway between Arcturis and Vega lies the constellation of Hecules. The Keystone of Hercules consists of the four stars in its center, and on its right hand side lies M13, the Great Globular Cluster, and the brightest in the Northern Hemisphere.The PlanetsJupiter stays close to Venus following their conjunction on June 30th. They both appear low in the western sky just after sunset. It is currently shining at magnitude -1.8, but dims to -1.7 magnitudes towards month's end. Its angular diameter will shrink from 32.4 to 31.2" over the month. Up to four of the Galilean moons and the dark equatorial bands will be visible, however the Great Red Spot will be harder to see without good seeing and transparency.Saturn is still well placed for observations in the south at nightfall. It moves slowly in retrograde motion in the eastern part of Libra, but still close to the fan of three stars which make up the head of Scorpius. It dims from +0.2 to +0.4 magnitudes, and its disk shrinks from 18.1 to 17.3" over the month. The ring system, tilted 24 degrees from the line of sight and spanning 40" across makes for a wonderful sight.Mercury will be sinking back towards the light of pre-dawn sky for the first part of the month. It will be best seen at the start of the month, with a magnitude of -0.2 and a phase of 52 percent. Its 7" diameter disk should just be visible with binoculars on the east-northeast horizon as dawn breaks.Mars is just 8' away from Mercury on the 16th of the month. Throughout the month it will be visible low above the north-eastern horizon before dawn breaks. It will brighten from +1.6 to +1.7 magnitudes over the month, while its disk, fully illuminated, will remain at an angular size of 3.6".Venus, shining brightly at magnitude -4.6, dominates the western sky from half an hour after sunset for the first part of the month. First appearing 19 degrees above the western horzon, and setting at 11:35 BST, it lies in Leo and moves towards, and then beyond, Regulus. On July 18th it will be joined by Jupiter, and by a thin crescent moon. It then wanders westward from July 23rd, before returning towards Jupiter on the 31st, when it will be 6 degrees south of the gas giant. Throughout the month it will increase in angular size from 33 to 51", and decrease in phase from 34 to 8 percent.HighlightsSaturn, and its moon Titan, [...]


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The night sky for May 2015

Fri, 05 Jun 2015 12:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during June 2015.The constellation of Leo the Lion is setting in the west after sunset, with the asterism of the Sickle forming its mane and Regulus as its brightest star. The planets Jupiter and Venus are both found here later in the month. Towards the South is the Realm of the Galaxies, in Virgo and Coma Berenices, where a telescope can pick out many deep-sky objects. The bright star Arcturus, in Bootes, resides nearby. Cygnus the Swan and Lyra the Lyre are rising in the east, with Hercules in between them and Bootes. The Summer Triangle, composed of the stars Altair in Aquila, Deneb in Cygnus and Vega in Lyra, is visible. One third of the way from Altair to Vega lies the Cygnus Rift, a dark region of dust in the Milky Way, which hosts Brocchi's Cluster, also known as the Coathanger. Ursa Major is almost overhead.The PlanetsJupiter is still bright in the south-west at nightfall. Its brightness declines from magnitude -1.9 to -1.8 during the month, while its angular size drops from 35 to 32.5". It moves from Cancer into Leo on the 9th and heads towards Regulus. Although the current apparition is past its best, a small telescope can still show Jupiter's equatorial bands and its four Galilean moons.Saturn reached opposition on the 22nd of May, so it is visible in the south-east after dark and crosses the southern sky during the night. It is moving retrograde (westwards) through the eastern part of Libra, close to the fan of three stars marking the head of Scorpius the Scorpion and only 3 degrees from the double star Beta Scorpii. The planet is 18" across, and the rings span 41", tilting at 24 degrees to the line of sight. However, Saturn's low elevation, never rising above 20 degrees from the UK, makes atmospheric blurring a problem when observing it closely.Mercury was at inferior conjunction (between the Earth and Sun) on the 30th of May, so it is not visible for the first part of June. It then climbs slowly into the pre-dawn sky, reaching western elongation (its greatest separation from the Sun in our sky) on the 24th. It has a magnitude of +0.5 and an illuminated fraction of 35 percent at this time, and should be visible just above the east-north-eastern horizon at dawn, with Aldebaran and the Hyades Cluster 2 degrees to its lower right. By month's end, Mercury is a little brighter and sits 6 degrees above the horizon 45 minutes before sunrise.[...]


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The night sky for May 2015

Fri, 01 May 2015 18:00:00 +0100

Northern HemisphereIan Morison tells us what we can see in the northern hemisphere night sky during May 2015.The winter constellations of Orion, Taurus and Gemini are setting in the west after sunset, with Auriga close behind. Leo is higher in the sky to their left, and further over is the bright star Arcturus in Bootes. Between them, in an otherwise fairly blank part of the sky, the Realm of the Galaxies offers 18 Messier objects to telescopic observers. The Summer Triangle rises in the east later in the evening, consisting of the bright stars Vega in Lyra, Deneb in Cygnus and Altair in Aquila. The constellation of Hercules is between Arcturus and Vega, and its four brightest stars make a trapezium called the Keystone. Two-thirds of the way up the Keystone's right-hand side, binoculars can locate the globular cluster M13. The asterism of the Plough is overhead, its hindmost stars, Merak and Dubhe, pointing towards Polaris in the north. Below Polaris is the W-shaped constellation of Cassiopeia.The PlanetsJupiter is in the south-south-west after dark. Receding from us, its brightness declines from magnitude -2.1 to -1.9 during the month, while its angular diameter decreases from 38 to 35". It moves eastwards from Cancer towards Leo, and a telescope shows its equatorial bands, Great Red Spot and Galilean moons. From 22:00 BST (British Summer Time, 1 hour ahead of Universal Time) on the 20th, observers can see the shadow of the moon Ganymede passing across Jupiter, followed by the moons Callisto and Io themselves.Saturn reaches opposition this month, when it is opposite the Sun in the sky and due south at around 01:00 BST.Mercury passed superior conjunction (behind the Sun in the sky) on the 10th of April, and can be seen low in the west after sunset in early May, a few degrees from the Pleiades Cluster in Taurus. It is best seen on the 7th, 22 degrees from the Sun in the sky at eastern elongation. Its brightness falls from magnitude -0.4 at the beginning of the month to +3.0 in the middle, when it becomes lost in the Sun's glare. At the same time, its angular size grows from 6.8 to 11".Mars may be just visible on the 1st, 9 degrees below the Pleiades Cluster and shining at magnitude +1.4, but is lost in the twilight after this. With an angular size of 3.8", it is too small for surface details to be seen.Venus shines brilliantly in the west after sunset, climbing from Taurus into Gemini and passing the star Epsilon Geminorum on the 16th. On the way to its greatest separation from the Sun in the sky on the 6th of June, it brightens from magnitude -4.2 to -4.4 and grows from 16 to 22" during May, while its illuminated fraction drops from 67 to 53 percent.HighlightsSaturn is well placed for observation this month, as it reaches opposition on the 23rd and is therefore visible for most of the night. The rings are inclined at 24 degrees to the line of sight, almost as visible as they can ever be. Saturn brightens to magnitude 0 during May, its brightest for 8 years, with the planet spanning 18.5" and the rings 42". Around the time of opposition, the lack of shadow on the ring system makes them appear brighter than usual, a phenomenon known as the Seeliger Effect. Saturn is moving retrograde (westwards) away from the double star Beta Scorpii and towards the constellation of Libra, which it reaches on the 12[...]


Media Files:
http://www.jodcast.net/archive/201505/20150501-jodcast-nightsky.mp3