The Night Sky February 2013
Compiled by Ian Morison
A third great month to view Jupiter and perhaps spot a Near Earth Object pass close by!
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
Spiral Galaxy NGC1309
Hubble Legacy Archive, ESA,NASA; processing by Martin Pugh.
NGC1309 is a type Sc spiral galaxy lying 100 million light years away in the constellation Eridanus. It has a diameter of 30,000 light years so is about one third the size of our Milky Way galaxy. Its distance has been found by observations of Cepheid variable stars. In February last year a type Ia Supernova was observed in the galaxy. Knowing its accurate distance, enabled its peak brightness to be calculated. As the brightness of this type of supernova is used to calculate the distance of remote galaxies, this has helped to calibrate the distance scale of the Universe. How many other galaxies can you spot in this beautiful image?
Highlights of the Month
February - a third great month to view Jupiter
This is the third of three great months to observe Jupiter. It now lies in Taurus and so is high in the ecliptic and hence, when due south, at an elevation of ~60 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 in the South Equatorial Belt. Jupiter was at opposition on the 3rd of December so, this month, will cross the meridian in the early evening - ideal for observing! After its apparition next year it will be moving towards more southerly parts of the ecliptic so will be at lower elevations when crossing the meridian and will thus be seen through thicker layers of the atmosphere.
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. The diagram on right 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.
See more of Damian Peach's images: Damian Peaches Website"
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.
1st 20:59 20th 21:43
3rd 22:37 22nd 23:22
6th 20:07 25th 20:53
8th 21:46 27th 22:32
February 8th - after sunset: Mercury and Mars.
On the evening of the 8th, Mercury (at -1 magnitude) will lie just 0.3 degrees to the upper right of Mars (at 1.2 magnitude). One of the very last chances to spot Mars this apparition. You will need a very good, low, western horizon and will probably need to use binoculars - but not until the Sun has set!
The evening of February 15th: a chance to spot a Near Earth Object as it passes close to the Earth.
If it is clear during the evening of February 15th we have a very rare chance of spotting a Near Earth Object, NEO 2012 DA14, as it passes the Earth within the orbits of the geostationaty satellites - thats close! Its closest approach is earlier in the day when it will pass just 31,000 kilometres above the Indian Ocean. With a brightness of around 7th magnitude at 8pm, binoculars should be able to spot it easily as it passes behind the tail of Leo the Lion. By 9 pm, its brightness will have dropped to 8.6 magnitude as it passes through Canes Venatici and by 9:30, as it crosses the handle of the Plough, its brightness will have dropped to 9th magnitude. As it will then be moving further away from Earth, its motion across the sky will be slowing down.
Please note: As this object is probably the closest to Earth that we might ever see (or hope to see!), parallax will determine its exact path across the sky as seen from your location. It is possible to print out a precise ephemeris by using the JPL Horizons website whose link is given below.
JPL website: Horizons WEB interface"
February 17th after sunset: Mercury at greatest eastern elongation
On the 17th, Mercury is furthest in angle from the Sun, called greatest elongation, so will be highest in the sky after sunset. Find a location with a good low western horizon and get there before the Sun sets. Perhaps 30 or so minutes later you should, if it were clear, be able to spot our innermost planet up and a little to the left of where the Sun has set. Binoculars may be needed at first but, providing that there is not too much haze, you should be able to spot it with the unaided eye.
February 18th evening: Jupiter with an 8 day old Moon.
During the evening of the 18th of February, the 8 day old Moon will lie to the east of Jupiter as it hangs between the Hyades and Pleiades open clusters.
February 23rd, evening: The Moon occults the open cluster M67 in Cancer.
During the evening of the 23rd of February, the (close to full) Moon will occult the open cluster M67 in Cancer starting at about 19:50 UT and ending at about 21:40. That evening it will also occult the stars 50 Cancri (before) and 60 Cancri (afterwards).
February 25th, early morning: Saturn's rings occult an 11.5 magnitude star
During the early hours of the 25rd of February, an 11.5 magnitude star will pass behind Saturn's rings. It might just be glimpsed as it passes behind Cassini's division at 01:30 UT but probably only if the seeing is very good. it might be easier to image with a CCD camera or web-cam. Later, it should emerge from behind the A ring at about 02:45. As is mentioned in the planetary details, Saturn has, by the 25th, started moving in retrograde motion - that is towards the west - which is why the star emerges to the east (left) of the rings.
It as the unexpected occultation of a star by the rings of Uranus that led to their discovery in 1977.
February 18th 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 Galaxy M109, 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|
|February 10th||February 17th||February 25th||February 3th|
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, in the constellationof Taurus. the Bull, is now high in the southern sky after sunset and crosses the meridian at 07:45 UT. By month's end it will transit at sunset so will be just west of south as darkness falls. When due south, it will lie some 60 degrees above the horizon. Shining at magnitude -2.5, it starts Feburary lying just 6 degrees to the upper right of the star Aldebaran, the eye of the Bull, towards the Pleiades Cluster. Jupiter ended its retrograde motion (westwards across the sky) on the 28th of January, so whilst its magnitude drops slightly to -2.3 it moves very slowly eastwards across the sky as the month progresses ending up just over 5 degrees to the upper right of Aldebaran. During the month its angular diameter drops slightly from 42.4 to 39.7 arc seconds so even a small telescope will still show plenty of detail with the bright zones and darker bands crossing the disk and up to four Gallilean moons visible as they weave their way around the giant planet. The times given in the highlight above will tell you when the Great Red Spot is easily visible in the evening.
See highlights above.
Saturn, lying in Libra, rises at 01:00 UT as the February begins and by 11:30 UT by month's end and will transit before dawn at an elevation of 25 degrees. Its magnitude remains almost constant at +0.5 magnitudes whilst its angular size increases from 17.2 to 17.8 arc seconds. The good news is that the rings have now opened out to just over 19 degrees from the line of sight and will be at their best for 6 years! We are now observing the planet's southern hemisphere whilst much of the northern hemisphere will be hidden by the rings. As February begins,Saturn will be at ~90 degrees in angle from the Sun and so will then be side-lit and showing the shadow of the planet on the rings. For the first half of the month, Saturn moves very slowly towards the wide double star Alpha Librae with the seperation dropping to 4.2 degrees on the 15th, but it then starts its retrograde motion westwards so gradually moves away. With a small scope one should now be able to spot Cassini's Division within the rings if the "seeing" is good along with Saturn's largest Moon, Titan. Sadly, Saturn is now lying in the more southerly part of the ecliptic so its elevation does not get that high when seen from our northern latitude - and this will get worse for quite a few years.
See highlight above.
Mercury, reaches eastern elongation (when it is furthest from the Sun in angle) on the 17th and will provide us with our best evening views of the planet this year. As the month begins, it shines at magnitude -1.1 but still hard to spot in the twilight. Its good to get to a site with a low western horizon before sunset and note where the Sun sets on the horizon. Then it is safe to sweep the sky with binoculars up and to the left of where the Sun had set. Once found and as the sky darkens, it should be easy to see with the unaided eye. small telescope will show a 5.2 arc second disc which is 95% illuminated. As the month progresses its brightness will fall to +1.5 whilst its angular size increases to 9 arc seconds.
See highlight above.
Mars, having just moved into Aquarius, is still visible low in the west after sunset - as it has been for around 5 months now! It can just be seen at an elevation of about 6 degrees in the southwest 45 minutes after sunset on Feb 1st but, by month's end, will have been lost in the Sun's glare. It shines at magnitude +1.2 but, with an angular diameter of 4 arc seconds and given its very low elevation, no surface markings will be seen on its salmon-pink disk.
See highlight above.
Venus. is now passing behind the Sun and, with an elevation of just 3 degrees as the Sun sets on February 1st will be almost impossible to spot. It will reach superior conjunction, when it lies directly behind the Sun, on the 30th of March, so will not be visible again until towards the end of May - but then in the evening sky after the Sun has set.
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.