The Night Sky February 2012
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
Little Ghost Planetary Nebula
Hubble Heritage Team, ESA/HUBBLE and NASA
This image shows the Little Ghost Planetary Nebula which was discovered by William Herschel in the constellation Ophiuchus. Named "Planetary Nebula" as some have the appearance of a planet, they are, in fact, the remnant of stars like our Sun whose collapsed core has formed a "White Dwarf" about the size of the Earth. The ring structure is about a light year across and the image has been captured in the light emitted by ionized oxygen, hydrogen and nitrogen which have been given the colours blue, green and red respectively. Lying over 2000 light years away, it shows us how our own Sun may appear in around 5 billion years from now.
Highlights of the Month
February 3rd before dawn: Two Globular Clusters and Comet Garradd
Visible in the east at ~6:30 am will be the bright star Vega in Lyra. Up and a little to the right is the constellation of Hercules whose most prominent stars make up the Keystone - but seen on its side at this time. Just above the line joining the upper two stars of the keystone is the best globular cluster to observe in the northern hemisphere, M13. At magnitude 6, this is easily seen in binoculars. To the left of the keystone when seen at this angle lies M92 at magnitude 6.5. This would be observed far more often if it were not overshadowed by M13! During February, running up to the right of M92 is comet Garradd, expected to be at magnitude ~7, so again, binoculars should be able to pick it out on a dark night. Happily, as it passes closest to M92 on the 3rd of February, the Moon will have set at 3:40 am so its light will not hinder your view.
February 9th at 9pm : Mars close to a 17 day old Moon
As Mars rises in the eastern sky on the 9th of February it will be accompanied by the Moon just two days after full.
February 12th - before dawn: Saturn, Spica and a waning Moon
Before dawn on the 16th January looking west of south there is a nice grouping of Saturn, Spica and a 20 day old waning Moon. The three will lie in an almost straight line.
February 25th: Jupiter,Venus and Mercury with a thin crescent Moon.
After sunset at about 6 pm on the 25th, you may, given a low south western horizon and clear skies, be able to spot Venus, at magnitude -4 just to the left of a thin crescent Moon. Look out for the "earthshine" illuminating the "dark side" of the Moon - often called the "old Moon in the new Moon's arms". Jupiter, at magnitude -2, will also be in view up to the left and, with luck, you may also spot Mercury, at magnitude -1, down to the lower right. A lovely grouping of the Moon and planets!
Find M31 - The Andromeda Galaxy - and perhaps M33 in Triangulum
In the early evening, the galaxy M31 in Andromeda is visible in the south-west lying a little below the line joining Jupiter to the "W" shaped constellation Cassiopeia. The chart provides two ways of finding it:
1) It will lie almost directly above the square of Pegasus which will be up to the right of Venus in mid month. Start at the top left star of the square - Alpha Andromedae - and move two stars to the left and round a bit. Then turn 90 degrees to the right, move down 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!
2) You can also find M31 by following the "arrow" made by the three rightmost bright stars of Cassiopeia down to the lower left as shown on the chart.
The accompanying image was the first ever taken by the author with a SBIG ST-8300M 8 Mpixel CCD camera mounted on an 80mm Ed refractor from somewhat light polluted and hazy skies near Shrewsbury late November. Perhaps not too bad for a first attempt. M32 is the spherical dwarf elliptical above and M101 the more elongated elliptical below.
Around the night of new Moon (21st February) 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 a bit brighter than the sky background. Good Hunting!
February: Look for the Great Red Spot on Jupiter
This list gives some the best times during February to observe the Great Red Spot which should then lie close to the central meridian of the planet. The GRS can move in position around the surface and a second set of calculations puts the times of transit a little later than those given.
2nd 23:13 22nd 19:53
5th 20:44 24th 21:32
7th 22:23 26th 23:12
10th 19:54 29th 20:43
February 29th Evening: The Hyginus Rille
For 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 that the overlying surface collapsed into it so forming the crater.
M109 imaged with the Faulkes Telescope
The Trapezium in M42, imaged by Daniel Duggan.
This image was taken using the Faulkes Telescope North by Daniel Duggan - for some time a member of the Faulkes telescope team. It shows the barred spiral galaxy M109 that lies at a distance of 83 million light years in the constellation of Ursa Major. It is the brightest galaxy in the Ursa Major group of some 50 galaxies. Our own Milky Way galaxy is now thought to be a barred spiral like M109.
Learn more about the Faulkes Telescopes and how schools can use them: Faulkes Telescope"
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 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|
|Feb 21st||N/A||Feb 7th||Feb 14th|
Some Lunar Images by Ian Morison, Jodrell Bank Observatory: Lunar Images
A World Record Lunar Image
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.
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.
Jupiter is still beautifully seen in the evening sky transiting due south just half an hour after sunset as February begins. On Febuary 1st it will the lie some ~50 degrees above the southern horizon shining at magnitude -2.4 in Aries close to its boundary with Pisces. With an angular size of ~38.7 arc seconds falling to 36.5 during the month, a small telescope will easily show the equatorial belts (the south equatorial belt has reappeared) and the four Galilean moons. Use the details in the highlight above to spot the Great Red Spot (actually a pale yellow-orange to my eyes) lying in an indentation of the south equatorial belt. Observing it in the last few weeks has shown some prominent dark regions in the north equatorial belt. These are called "barges". I do hope that you will have taken my advice and bought a small telescope to observe it!See highlights above.
Saturn rises at mignight at the beginning of the month, and can be seen due south at an elevation of 31 degrees at around 5:30 am. By the end of February, it rises at 10 pm and will lie in the south at around 3:30 am. It lies in Virgo, shining at magnitude +0.6 (increasing to +0.5 during the month) some 7 degrees slightly up and to the left of the first magnitude star Spica. Sadly, in contrast to Jupiter, Saturn is heading to the more southerly parts of the ecliptic so, for quite some considerable time, will not be seen high above the horizon. However, nicely, the rings are opening out and are now ~15 degrees to the line of sight, so will appear appreciably wider than we have seen during its last apparition. It is now well be worth having a look at its ~18 arc second disk and ring system. With a small telescope on a night of good seeing, you should now be able to easily spot Cassini's Division within the ring system, and given a scope with an aperture of 6 inches or greater and a night of excellent seeing one might even spot Encke's division in the outer A-ring and also the inner, elusive, C-ring.
Mercury, passes behind the Sun on February 6th (superior conjunction), so will not be visible until it reappears in the sky towards the south-west after sunset in the last week of the month. With a 66% illuminated disk and shining at magnitude -1.1, it will be moving towards the Earth, with an (increasing) angular size of just under 6 arc seconds.See highlight above.
Mars. At the start of February Mars, moving retrograde from Virgo into the southern part of Leo, rises at 8:30 pm and will have risen to an elevation of ~46 degrees due south around 3 am. It brightens from -0.6 to -1.1 during the month, so is becoming more prominent. By month's end it rises at about 6 pm and, more importantly, will transit before 1 am at an elevation of 50 degrees below the lion's hind quarters. Its angular size increases from 12 arc to 14 seconds during the month and so it is now, given good seeing, becoming possible to observe features on the surface of its its salmon-pink disk. Details, such as the V shape of Syrtis Major and the north polar cap (which is tilted towards us), should now be visible. The markings on Mars are quite subtle and it is important that the scope has cooled down to ambient temperature to eliminate tube currents that limit the image quality.See highlight above.
Venus, prominent in the south-western sky after sunset, is now gradually increasing its angular separation from the Sun and, on Feb 1st, is 39 degreees away from the Sun and will have an elevation of ~30 degrees at sunset. It continues to draw away so that by month's end it will be 44 degrees away and a further 7 degrees above the horizon. Its angular size is increasing - from 15 to 18 arc seconds during the month - but as it does so its phase (the percentage that we see illuminated) is falling from 74 to 64%. One interesting result is that Venus's brightness stays remarkably constant at magnitude -4.1 throughout the month. Observing Venus through a deep blue filter may enable one to see a hint of the cloud structure in its atmosphere, but it is very subtle!
See highlight above.
Find more planetary images and details about the Solar System: The Solar System
The Mid Evening February Sky
This map shows the constellations seen in the south during the 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 constellation Taurus
Taurus is one of the most beautiful constellations and you can almost imagine the Bull charging down to the left towards Orion. His face is delineated by the "V" shaped cluster of stars called the Hyades, his eye is the red giant star Aldebaran and the tips of his horns are shown by the stars beta and zeta Tauri. Although alpha Tauri, Aldebaran, appears to lie amongst the stars of the Hyades cluster it is, in fact, less than half their distance lying 68 light years away from us. It is around 40 times the diameter of our Sun and 100 times as bright.
To the upper right of Taurus lies the open cluster, M45, the Pleiades. Often called the Seven Sisters, it is one of the brightest and closest open clusters. The Pleiades cluster lies at a distance of 400 light years and contains over 3000 stars. The cluster, which is about 13 light years across, is moving towards the star Betelgeuse in Orion. Surrounding the brightest stars are seen blue reflection nebulae caused by reflected light from many small carbon grains. These relfection nebulae look blue as the dust grains scatter blue light more efficiently than red. The grains form part of a molecular cloud through which the cluster is currently passing. (Or, to be more precise, did 400 years ago!)
Close to the tip of the left hand horn lies the Crab Nebula, also called M1 as it is the first entry of Charles Messier's catalogue of nebulous objects. Lying 6500 light years from the Sun, it is the remains of a giant star that was seen to explode as a supernova in the year 1056. It may just be glimpsed with binoculars on a very clear dark night and a telescope will show it as a misty blur of light.
Its name "The Crab Nebula" was given to it by the Third Earl of Rosse who observed it with the 72 inch reflector at Birr Castle in County Offaly in central Ireland. As shown in the drawing above, it appeared to him rather lile a spider crab. The 72 inch was the world's largest telelescope for many years. At the heart of the Crab Nebula is a neutron star, the result of the collapse of the original star's core. Although only around 20 km in diameter it weighs more than our Sun and is spinning 30 times a second. Its rotating magnetic field generate beams of light and radio waves which sweep across the sky. As a result, a radio telescope will pick up very regular pulses of radiation and the object is thus also known a Pulsar. Its pulses are monitored each day at Jodrell Bank with a 13m radio telescope.
The constellation Orion
Orion, perhaps the most beautiful of constellations, will be seen in the south at around 11 - 12 pm during January. Orion is the hunter holding up a club and shield against the charge of Taurus, the Bull up and to his right. Alpha Orionis, or Betelgeuse, is a read supergiant star varying in size between three and four hundred times that of our Sun. The result is that its brightness varies somewhat. Beta Orionis, or Rigel, is a blue supergiant which, at around 1000 light years distance is about twice as far away as Betelgeuse. It has a 7th magnitude companion. The three stars of Orion's belt lie at a distance of around 1500 light years. Just below the lower left hand star lies a strip of nebulosity against which can be seen a pillar of dust in the shape of the chess-board knight. It is thus called the Horsehead Nebula. It shows up very well photographically but is exceedingly difficult to see visually - even with relativly large telescope.
Beneath the central star of the belt lies Orion's sword containing one of the most beautiful sights in the heavens - The Orion Nebula. It is a region of star formation and the reddish colour seen in photographs comes from Hydrogen excited by ultraviolet emitted from the very hot young stars that make up the Trapesium which is at its heart. The nebula, cradling the trapesium stars, is a beautiful sight in binoculars or, better still, a telescope. To the eye it appears greenish, not red, as the eye is much more sensitive to the green light emitted by ionized oxygen than the reddish glow from the hydrogen atoms.
The constellation 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.
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).
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.
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.