February skies continue to be long, dark and clear; perfect for spotting some of the most prominent and beautiful stars. Vernon from the Callander and West Perthshire U3A Astronomy group shares what to look out for this month.
It is always helpful to have a star chart to follow when navigating and observing the heavens. A free star chart which also contains lots of additional observational notes is published monthly by Skymaps. Simply go to skymaps.com and scroll down to ‘Download the latest issue’. From here you will can download the northern hemisphere version and save it. This is then best printed double sided to an A4 sheet. It is worth noting that planets do not appear on skymaps. In this note of astronomical events I have only included items that can be seen either with the naked eye or with a pair of binoculars.
Should you venture outside you will need a torch. Use a red light head torch if you have one, or put red plastic over a torch to illuminate the skymap and preserve your night vision which improves greatly over time. Wrap up warm and with a little perseverance, about 20 minutes, you will feast your eyes on the universe that you live within. Enjoy and indulge!
Orion the Hunter continues to be one of the clearest constellations (see January Skylights) along with Gemini which is a little higher straddling the Milky Way. Castor and Pollux are the two prominent stars at the head of the constellation while rarely considered Alhena, a “foot” star, which sits at the base. Pollux is the brighter of the twins sitting below Castor and is a single orange giant around 34 Light Years away. Castor is fainter and above making it closer to the celestial North Pole which has the constellation of Lynx (introduced in 1687 by the famous astronomer Johannes Hevelius to fill in the large blank area between Auriga, Gemini and Ursa Major) passing through it. Castor has a surprise in that it is not one star at all but a multiple of six individual stars, four blue white and two red dwarfs. The Romans associated the “two” stars with the twins Romulus and Remus, the founders of Rome itself. However, their common names represent the twin sons of the Spartan Queen Leda, mortal Castor and immortal Pollux, who joined Jason’s crew in the quest for the golden fleece.
Next to the constellation lies the Eskimo Nebula, NGC 2392, which has been beautifully photographed from the Hubble Telescope, image on the right.
Sirius, remains the brightest star in the night sky with twice the mass and just under twice the diameter of the Sun. It emits 26 times as much energy as the Sun and is just over 8.5 light years from the Earth.
Looking Directly Overhead
Looking directly overhead we can see the pentagon shape of Auriga, the Charioteer. It is quite easy to pick out once you know that Capella is at the top. Capella is easily identified because it has a triangle of three feinter stars alongside it. These are usually referred to as the Haedi or Kids, as this part of the sky combines the legends of the heroic Greek charioteer and the herd of goats more familiar to Middle Eastern peoples. Some old star atlases that include drawings of the myths lumber the charioteer with the kids around his neck. Capella is a yellowish colour and this contrast well with the bluish colour of Rigel in the constellation of Orion, which is of the same brightness.
Looking north Ursa Major, the Great Bear continues to dominate and details of the constellation were covered in January Skylights. Ursa Minor with Pole Star, Polaris takes centre stage wrapped round by Drago while hemmed in by Cephus and Camelopardalis. To the west the constellation of Andromeda can continue to be seen before it starts to drift ever westward towards the horizon at the end of the month. This allows Coma Berenices to enter the foreground from the east. Coma Berenices, though feint and unremarkable to the naked eye is a true beauty when viewed in clear dark conditions with binoculars. It is home to one of the closest star clusters to Earth and has distant galaxies that can be seen with minimal interference because of its location in the sky. Coma, as it is often known, was named to honour a historical, rather than mythological figure, Queen Berenice, who was the wife of third century ruler of Egypt, Ptolemy III. She is said to have made an oath with goddess Aphrodite promising to cut off her hair in return for her husband’s safety from battle. When Ptolemy returned in good health, this patch of starry sky was renamed in her honour.
Mercury is still an evening object at the beginning of the month before it vanishes below the horizon on the 5th.
Venus now a low morning star at the start the month until it is fully obscured by the rising sun at the end of February. Passes half a degree from Jupiter on 8th.
Earth experiences the most distant lunar perigee of the year on 3rd, 370,000km.
Mars is getting feinter by every passing night. It occupies the constellation of Aries until 23rd when it moves into Taurus.
Jupiter shining at magnitude -2 and Venus at -3.9 approach within half of a degree of each other on 11th February. At this point they are only 11 degrees from the Sun and deep in the dawn twilight
Saturn following last month’s Great Conjunction Saturn reappears ahead of the morning Sun in the constellation of Capricornus. Best at the end of the month about an hour before sunrise.
Uranus is a sixth magnitude object in the constellation of Aries and is visible in the evening sky setting around midnight. Can be seen close to a waxing crescent Moon on 17th.
Neptune is in the constellation of Aquarius for the whole year. As it is setting ever earlier as the month progresses it is best to look for it early in the month before it is lost in the twilight.
Nights of particular interest
Some of the objects described below are expressed in degrees from the Moon. This is far less complicated to measure than you might think. To measure 10 degrees, hold your hand up towards the sky at arm’s length and turn your hand up so that it obscures part of your view. The width of your hand is 10 degrees and holding just one finger is two degrees.
3rd 19.03 Moon at perigee (370,127km)
4th 17.37 Moon Last quarter
6th 05.00 Saturn half a degree from Venus
6th 06.30 Moon is 5 degrees north of Antares, Sabik is 12 degrees southeast
10th 20.25 Venus 3.2 degrees north of the Moon
10th 21.35 Jupiter 3.7 degrees north of the Moon
11th 19.06 New Moon
17th 15.48 Uranus 3.7 degrees north of the Moon
18th 10.22 Moon at apogee (404,467km)
18th 22.46 Mars 3.7 degrees north of the Moon
19th 18.47 Moon First quarter
19th 23.00 Moon passes between Aldebaran and Pleiades. Mars just below Pleiades and only slightly brighter than Aldebaran
21st 00.00 Using binoculars will reveal the clair-obscur effect know as the Jewelled Handle. It is caused when the mountain range bordering Sinus Iridium catches the lunar dawn.
22nd Minor planet, 29 Amphitrite, reaches opposition at magnitude +9.1 in Leo. Unfortunately, this is for telescopes only
24th 03.00 Moon with Castor and Pollux in western sky
26th 18.30 Moon passes between Algieba and Regulus
27th 08.17 Full Moon aka Snow Moon