Sky Notes for February 2013 #stargazing
The last month of winter is marked by the return to the late evening skies of the bright star Arcturus, a herald of spring. After 10pm, looking to the North East, Arcturus can be found by following the curve of the tail of Ursa Major downwards. The star has a strong orange colour and is located at a distance of over 30 light years from our Solar System and is over 100 times more luminous than our own Sun. It is also a strong candidate to be an “alien” star, stripped from a smaller galaxy that has been consumed by our massive Milky Way galaxy. Arcturus has an unusual galactic orbit and appears to form a group with other stars on a similar trajectory which are distinctively metal-poor.
Saturn returns to the late evening skies by the end of February, although low in the South East.
The winter constellations remain well on show but are best seen in the early evening now, with Orion just past South as it gets properly dark at 7.30pm at the end of the month. Jupiter remains well placed in Taurus but is starting to get low in the West by 11pm as February draws to a close.
Early spring is a good time of year to spot the young moon when it is still a very thin crescent. It is best to have a good clear Western horizon. At 7pm on the 12th the young Moon will be just 8% illuminated low in the West and on the following evening at the same time it will be 14% illuminated and higher in the sky. This is also a good opportunity to see Earthshine.
On the 18th the Moon once again makes a fairly close pass of Jupiter, the 2 objects being separated by only 4 degrees at 8pm. The Moon is Full on February 25th.
Daylight increases rapidly through the month, with sunset taking place after 5.30pm by the end of February.
Next month sees the possibility of a bright comet in the evening skies. C/2011 L4 (Pan-STARRS) is currently visible in the Southern hemisphere at around mag 7. There are a range of estimates of how bright it will become as it emerges into northern skies after perehelion on March 10th. It has a hyperbolic orbit (eccentricity greater than 1) and, as Sky and Telescope reports, that indicates that this is a new comet falling in from the Oort Cloud. Such comets can brighten early but then the rate of brightening slows. Currently the predictions are tending towards a peak brightness of mag 3, which is a long way off the early predictions of mag -1.
As the comet retreats from the Sun it will always be low in the West and later the North West from Essex – and in twilight. So we are going to need 3 factors in our favour if this is to be a prominent object – it must be bright, observers will need a good line of sight down to the Western horizon and not least – transparent and clear skies!
James Abbott is an astronomer, NEAS member and CfDS Regional Information Officer.
Posted on 2 February, 2013, in Astronomy News, Popular Science, Stargazing and tagged arcturus, comet, january, jupiter, moon, orion, panstarrs, winter. Bookmark the permalink. Comments Off on Sky Notes for February 2013 #stargazing.