The Night Sky March 2010
Compiled by Ian Morison
This page, updated monthly, will let you know some of the things that you can look out for in the night sky. It lists the phases of the Moon, where you will see the naked-eye planets and describes some of the prominent constellations in the night sky during the month.
Image of the Month
Andromeda galaxy in the Infrared. Image:NASA/JPL-Caltech/UCLA
This wonderful infrared image of the Andromeda Galaxy has just been taken by WISE, the Wide-field Infrared Survey Explorer which began a 6 month infrared survey of the sky in January. The mosaiced image also shows M31's two daughter galaxies M110 below and M32 just above the bright ring of emission which indicates a circular region of star formation.
Highlights of the Month
Saturn, Mars and the Asteroid Vesta
Saturn, Mars and a chance to spot an asteroid.
Image:Stellarium/IM
Saturn, Mars and a chance to spot the asteroid Vesta.
The chart of the eastern sky in mid evening show the location of Saturn, in Virgo, and Mars in Cancer. Neither change much in position during the month as Saturn is far away and Mars is coming to a stationary point where it begins to move eastwards across the sky again after its retrograde motion from Leo into Cancer. Details about Saturn and Mars are given in the "Planets" section below. You could also use binoculars to spot the asteroid Vesta, the brightest (though not the largest, Ceres) of the main belt asteroids that lie between Mars and Jupiter. On February 16th, I was able to show my astronomy class Vesta as it passed between Algieba and 40 leonis. It is now heading up towards the upper right star of the "Sickle" and only 4 stars are brighter than Vesta in this region so it should be reasonably easy to spot at ~6th magnitude. If you sketched the positions of the brighter "stars" within the sickle on a couple of nights you should be able to see which has moved!
Evening March 31st: Venus and Mercury together after Sunset.
Venus and Mercury in the evening sky
Image:Stellarium/IM
Venus and Mercury close in the twilight sky
Given a low westerly horizon and a clear night you will have a chance to see Venus and Mercury just 3.3 degrees apart about 30 minutes after sunset. Both are moving away from the Sun so getting higher in the sky after sunset. Their closest approach, at 3 degrees separation, will be on April 4th so keep watchin over the next few days.
Have a good look at the Hyades and Pleiades Clusters.
The Hyades and Pleiades Open Clusters
Image: Stellarium/IM
The two nearest open clusters to us - the Hyades and Pleiades Clusters are high in the sky after sunset so March is still a good month to observe them. The Pleiades Cluster is one of the youngest open clusters and is dominated by blue stars that have been formed within the last 100 million years. None have yet evolved into red giant stars - so helping to define its age. It appears to be passing through a cloud of dust which is scattering the blue light form the stars forming so called "reflection nebulae" around the brighter stars of the cluster. The Pleiades are a lovely sight in high power binoculars or a short focal length telescope. The closer Hyades Cluster is older and does contain some evolved stars. The stars Aldebaran, the eye of the Bull, lies about halfway between the Hyades Cluster and the Earth so is not part of it.
Observe a White Dwarf
Eridanus
This is a good month to try to observe a White Dwarf star - the end state of a star like our own Sun. They are about the size of the Earth, but are very hot so can still appear reasonably bright. Omicron-2 is an orange star of magnitude 4.4 in the constellation Eridanus that lies to the right of Rigel. You will be able to pick this up with a pair of binoculars. However if you can use a small telescope with medium power you should spot a faint white 9th magnitude companion - a white dwarf. White dwarfs are very dense and a teaspoon full might weigh as much as a ton! Near the White Dwarf is an 11th magnitude "Red Dwarf" that might be spotted as well.
Observe the Open Cluster M41
Canis Major showing the position of M41
Open Cluster M41
As Sirius is high in the sky during the early evening this month, it is easy to find a nice open cluster - the 41st enty in the Messier Catalogue. It only contains about 100 stars, but some of these are bright "red giant" stars which appear orange to our eyes and make a very nice contrast with the others. It can easily be picked out with binoculars and makes a very nice sight in a small telescope - simply find Sirius and drop the field of view downwards and a touch to the left. As M41 is 4 degrees below Sirius, if you place Sirius at the very top of the field, M41 should appear at the bottom. Simples. M41 lies at a distance of about 2300 light years and is around 200 million years old.
Observe the International Space Station
The International Space Station and Jules Verne passing behind the Lovell Telescope on April 1st 2008.
Image by Andrew Greenwood
Use 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. (Across the world too for foreign visitors to this web page.)
Note: I observed the ISS three times recently and was amazed as to how bright it has become.
Find details of sighting possibilities from your location from: Location Index
See where the space station is now: Current Position
The Moon
The Moon at 3rd Quarter. Image, by Ian Morison, taken with a 150mm Maksutov-Newtonian and Canon G7.
Just below the crator Plato seen near the top of the image is the mountain "Mons Piton". It casts a long shadow across the maria from which one can calculate its height - about 6800ft or 2250m.
| new moon | first quarter | full moon | last quarter |
|---|---|---|---|
| March 15th | March 23rd | March 30th | March 7th |
Some Lunar Images by Ian Morison, Jodrell Bank Observatory: Lunar Images
A World Record Lunar Image
The 9 day old Moon.
To mark International Year of Astronomy, a team of british astronomers have made the largest lunar image in history and gained a place in the Guinness Book of Records! The whole image comprises 87.4 megapixels with a Moon diameter of 9550 pixels. This allows details as small as 1km across to be discerned! The superb quality of the image is shown by the detail below of Plato and the Alpine Valley. Craterlets are seen on the floor of Plato and the rille along the centre of the Alpine valley is clearly visible. The image quality is staggering! The team of Damian Peach, Pete lawrence, Dave Tyler, Bruce Kingsley, Nick Smith, Nick Howes, Trevor Little, David Mason, Mark and Lee Irvine with technical support from Ninian Boyle captured the video sequences from which 288 individual mozaic panes were produced. These were then stitched together to form the lunar image.
Plato and the Alpine Valley.
Please follow the link to the Lunar World Record website and it would be really great if you could donate to Sir Patrick Moore's chosen charity to either download a full resolution image or purchase a print.
The Planets
A montage of the Solar System. JPL / Nasa
Jupiter
A Cassini image of Jupiter . Nasa
Jupiter, having passed behind the Sun on the 28th February, reappears in the pre-dawn sky at the very end of the month. On the last day of March it will rise about 50 minutes before the Sun and, at magnitude -2, could be seen in binoculars given a clear low eastern horizon. Probably best to wait a month or two!
Saturn
The planet Saturn. Cassini - Nasa
Saturn rises by 8pm on March 1st (along with a full moon!) so can be seen, at magnitude +0.6, much of the night. It reaches "opposition", when it is roughly due south at midnight, on March 21st then rising aound sunset. The angular size of the disc stays around 19.5 arc seconds during the month with the rings extending to 44 arc seconds. The ring system is still close to edge on (its tilt angle is 4 degrees at the beginning of the month) and so will still appear very thin - the reason why Saturn is not a bright as it is when the rings are more open. However, due to difference between the orbital inclinations of Saturn and the Earth, the tilt is actually reducing at the moment and drops to 3 degrees by month's end. By mid April this will have reduced to only 1.7 degrees before the rings finally begin to open out again from the end of June onwards. For the first time in 15 years we are now begining to see the northern face of the rings. A small telescope will easily show its brightest satellite, Titan at magnitude 7.8, and one of 8 inches or more aperture several more.
See highlight above.
Mercury
Messenger image of Mercury Nasa
Mercury passes behind the Sun on the 14th of the Month, but then appears in the twilight sky along with Venus during the last week of March. You might just spot it with binoculars on the 22nd, 20 minutes after sunset, when it will lie 9 degrees below Venus and just 3 degrees above the horizon. It then rapidly climbes higher in the sky and by the 31st it is just 3 degrees away from Venus when both are 10 degrees above the horizon about 30 minutes after sunset. Mercury will be at its best for some time during the first week of April - one of next month's highlights!
Mars
A Hubble Space Telescope image of Mars.
Jim Bell et al. AURA / STScI / Nasa
Mars remains prominent in the evening sky, following its "opposition" at the end of January. It will be well up in the south and thus highest in the sky around 8:30 GMT. On December 20th, Mars began its retrograde path westwards and returned from Leo into Cancer on January 9th. Now in Cancer, it will continue to move westwards through Cancer until March 8th when it will resume its eastwards track across the skies. This "retrograde motion" is because the Earth has been overtaking Mars on the "inside track". Its magnitude reduces from -0.6 to +0.1 during the month, whilst its angular size drops from 12 to 9 arc seconds.
Venus
Venus showing some cloud structure
Venus. During March, Venus will become prominent in the evening sky after sunset as it climbs higher in the sky At magnitude -3.9, it will be easily spotted - the brightest object in the night sky after the Moon. Look towards the south west about half an hour after sunset. With an angular size of just 10 arc seconds it will appear in a telescope as a virtually fully illuminated disc. It was this observation by Galileo that showed that Venus must orbit the Sun - should it, as in the Ptolomaic system, be moving in an epicycle between the Sun and the Earth, it could never show a fully illuminated disk! It is an interesting fact that Venus's brightness remains pretty constant at ~ -3.8 to -4 all the time that it is visible. As it nears the Earth, it become a thin crescent, but the fact that it is then much nearer to us means that the effective reflecting area remains virtually constant in apparent size.
Radar image showing surface features
Find more planetary images and details about the Solar System: The Solar System
The Stars
The Early Evening March Sky
The March Sky in the south - early evening.
This map shows the constellations seen in the south during the early evening. The brilliant constellation of Orion is 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 Pleaides 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 consteallation Canis Major. Up and to the left of Sirius is Procyon in Canis Minor. Rising in the East is the constellation of Leo, the Lion, with the planet Saturn up and to the right of Regulus its brightest star. Continuing in this direction towards Gemini is the faint constellation of Cancer with its open cluster Praesepe (also called the Beehive Cluster),the 44th object in Messier's catalogue. On a dark night it is a nice object to observe with binoculars. There is also information about the constellation Ursa Major,seen in the north, in the constellation details below.
The Late Evening March Sky
The March Sky in the south - late evening.
This map shows the constellations seen in the south around midnight.
The constellation Gemini is now setting towards the south-west and Leo holds pride (sic) of place in the south with its bright star Regulus. Between Gemini and Leo lies Cancer. It is well worth observing with binoculars to see the Beehive Cluster at its heart. Below Gemini is the tiny constellation Canis Minor whose only bright star is Procyon. Rising in the south-east is the constellation Virgo whose brightest star is Spica. Though Virgo has few bright stars it is in the direction of of a great cluster of galaxies - the Virgo Cluster - which lies at the centre of the supercluster of which our local group of galaxies is an outlying member.
The constellation Gemini
Gemini
Gemini - The Twins - lies up and to the left of Orion and is in the south-west during early evenings this month. It contains two bright stars Castor and Pollux of 1.9 and 1.1 magnitudes respectivly. Castor is a close double having a separation of ~ 3.6 arc seconds making it a fine test of the quality of a small telescope - providing the atmospheric seeing is good! In fact the Castor system has 6 stars - each of the two seen in the telescope is a double star, and there is a third, 9th magnitude, companion star 73 arcseconds away which is alos a double star! Pollux is a red giant star of spectral class K0. The planet Pluto was discovered close to delta Geminorum by Clyde Tombaugh in 1930. The variable star shown to the lower right of delta Geminorum is a Cepheid variable, changing its brightness from 3.6 to 4.2 magnitudes with a period of 10.15 days
M35 and NGC 2158
This wonderful image was taken by Fritz Benedict and David Chappell using a 30" telescope at McDonal Observatory. Randy Whited combined the three colour CCD images to make the picture
M35 is an open star cluster comprising several hundred stars around a hundred of which are brighter than magnitude 13 and so will be seen under dark skies with a relativly small telescope. It is easily spotted with binoculars close to the "foot" of the upper right twin. A small telescope at low power using a wide field eyepiece will show it at its best. Those using larger telescopes - say 8 to 10 inches - will spot a smaller compact cluster NGC 2158 close by. NGC 2158 is four times more distant that M35 and ten times older, so the hotter blue stars will have reached the end of their lives leaving only the longer-lived yellow stars like our Sun to dominate its light.
The Eskimo Nebula, NGC2392, Hubble Space Telescope
To the lower right of the constellation lies the Planetary Nebula NGC2392. As the Hubble Space Telescope image shows, it resembles a head surrounded by the fur collar of a parka hood - hence its other name The Eskimo Nebula. The white dwarf remnant is seen at the centre of the "head". The Nebula was discovered by William Herschel in 1787. It lies about 5000 light years away from us.
The constellation Leo
Leo
The constellation Leo is now in the south-eastern sky in the evening. One of the few constellations that genuinely resembles its name, it looks likes one of the Lions in Trafalger Square, with its main and head forming an arc (called the Sickle) to the upper right, with Regulus in the position of its right knee. Regulus is a blue-white star, five times bigger than the sun at a distance of 90 light years. It shines at magnitude 1.4. Algieba, which forms the base of the neck, is the second brightest star in Leo at magnitude 1.9. With a telescope it resolves into one of the most magnificent double stars in the sky - a pair of golden yellow stars! They orbit their common centre of gravity every 600 years. This lovely pair of orange giants are 170 light years away.
Leo also hosts two pairs of Messier galaxies which lie beneath its belly. The first pair lie about 9 degrees to the west of Regulus and comprise M95 (to the east) and M96. They are almost exactly at the same declination as Regulus so, using an equatorial mount, centre on Regulus, lock the declination axis and sweep towards the west 9 degrees. They are both close to 9th magnitude and may bee seen together with a telescope at low power or individually at higher powers. M65 is a type Sa spiral lying at a distance of 35 millin klight years and M66, considerably bigger than M65, is of type Sb. Type Sa spirals have large nuclei and very tightly wound spiral arms whilst as one moves through type Sb to Sc, the nucleus becomes smaller and the arms more open.
The galaxies M65 and M66
M65 - Type Sa spiral, 9.3 magnitude M66 - Type Sb spiral, 8.9 magnitude
The second pair of galaxies, M95 and M96, lie a further 7 degrees to the west between the stars Upsilon and Iota Leonis. M95 is a barred spiral of type SBb. It lies at a distance of 38 million light years and is magnitude 9.7. M96, a type Sa galaxy, is slightly further away at 41 million light years, but a little brighter with a magnitude of 9.2. Both are members of the Leo I group of galaxies and are visible together with a telescope at low power.
The galaxies M95 and M96
M95 - Type SBb spiral, 9.7 magnitude M96 - Type Sa spiral, 9.2 magnitude
There is a further ~9th magnitude galaxy in Leo which, surprisingly, is in neither the Messier or Caldwell catalogues. It lies a little below lambda Leonis and was discovered by William Herschel. No 2903 in the New General Catalogue, it is a beautiful type Sb galaxy which is seen at somewhat of an oblique angle. It lies at a distance of 20.5 million light years.
The 8.9th magnitude, type Sb, Galaxy NGC2903
The constellation Virgo
Virgo
Virgo, rising in the east in late evening this month, is not one of the most prominent constellations, containing only one bright star, Spica, but is one of the largest and is very rewarding for those with "rich field" telescopes capable of seeing the many galaxies that lie within its boundaries. Spica is, in fact, an exceedingly close double star with the two B type stars orbiting each other every 4 days. Their total luminosity is 2000 times that of our Sun. In the upper right hand quadrant of Virgo lies the centre of the Virgo Cluster of galaxies. There are 13 galaxies in the Messier catalogue in this region, all of which can be seen with a small telescope. The brightest is the giant elliptical galaxy, M87, with a jet extending from its centre where there is almost certainly a massive black hole into which dust and gas are falling. This releases great amounts of energy which powers particles to reach speeds close to the speed of light forming the jet we see. M87 is also called VIRGO A as it is a very strong radio source.
The Giant Elliptical Galaxy M87 HST image showing the jet
Below Porrima and to the right of Spica lies M104, an 8th magnitude spiral galaxy about 30 million light years away from us. Its spiral arms are edge on to us so in a small telescope it appears as an elliptical galaxy. It is also known as the Sombrero Galaxy as it looks like a wide brimmed hat in long exposure photographs.
M104 - The Sombrero Galaxy
The constellation Ursa Major
Ursa Major
The stars of the Plough, shown linked by the thicker lines in the chart above, form one of the most recognised star patterns in the sky. Also called the Big Dipper, after the soup ladles used by farmer's wives in America to serve soup to the farm workers at lunchtime, it forms part of the Great Bear constellation - not quite so easy to make out! The stars Merak and Dubhe form the pointers which will lead you to the Pole Star, and hence find North. The stars Alcor and Mizar form a naked eye double which repays observation in a small telescope as Mizar is then shown to be an easily resolved double star. A fainter reddish star forms a triangle with Alcor and Mizar.
Ursa Major contains many interesting "deep sky" objects. The brightest, listed in Messier's Catalogue, are shown on the chart, but there are many fainter galaxies in the region too. In the upper right of the constellation are a pair of interacting galaxies M81 and M82 shown in the image below. M82 is undergoing a major burst of star formation and hence called a "starburst galaxy". They can be seen together using a low power eyepiece on a small telescope.
M81 and M82
Another, and very beautiful, galaxy is M101 which looks rather like a pinwheel firework, hence its other name the Pinwheel Galaxy. It was discovered in1781 and was a late entry to Messier's calalogue of nebulous objects. It is a type Sc spiral galaxy seen face on which is at a distance of about 24 million light years. Type Sc galaxies have a relativly small nucleus and open spiral arms. With an overall diameter of 170,000 light it is one of the largest spirals known (the Milky Way has a diameter of ~ 130,000 light years).
M101 - The Ursa Major Pinwheel Galaxy
Though just outside the constellation boundary, M51 lies close to Alkaid, the leftmost star of the Plough. Also called the Whirlpool Galaxy it is being deformed by the passage of the smaller galaxy on the left. This is now gravitationally captured by M51 and the two will eventually merge. M51 lies at a distance of about 37 million light years and was the first galaxy in which spiral arms were seen. It was discovered by Charles Messier in 1773 and the spiral structure was observed by Lord Rosse in 1845 using the 72" reflector at Birr Castle in Ireland - for many years the largest telescope in the world.
M51 - The Whirlpool Galaxy
Lying close to Merak is the planetary nebula M97 which is usually called the Owl Nebula due to its resemblance to an owl's face with two large eyes. It was first called this by Lord Rosse who drew it in 1848 - as shown in the image below right. Planetary nebulae ar the remnants of stars similar in size to our Sun. When all possible nuclear fusion processes are complete, the central core collpses down into a "white dwarf" star and the the outer parts of the star are blown off to form the surrounding nebula.
M97 - The Owl Planetary Nebula Lord Rosse's 1848 drawing of the Owl Nebula
