Cloud cover continues to make observing a bit of a challenge but we have had the odd clear sky recently and what a delight it was to see Orion as beautiful as ever.
The chart below represents the south facing night sky at 10.00pm on the 8th February and at 9.00pm on the 23rd February. Again Orion and the Winter Triangle (formed by Betelgeuse, Sirius and Procyon) provide all the navigational help required. Last month we were spoilt with all the wonderful bright stars on display but this month you will need to find a dark sky location to observe some dimmer objects. Perhaps you need to have your lockdown exercise walk in the evening to a suitable site free from light pollution. Of course the bright stars are still there but we will be concentrating more on the region to the east of them.
To the north-east of Orion it is easy to pick out the bright stars Castor and Pollux in the constellation Gemini- The Twins, but there is more to the constellation than just those two stars. The bodies of the twins are represented by two lines of faintish stars ending with their feet in the Milky Way. These stars are typically of magnitude 3 to 4 and may be a bit of a challenge depending on light conditions but there is a magnitude 1.9 star, Alhena, representing the feet of Pollux and you should be able to pick it out on a line from Betelgeuse to Pollux.
Now to three new constellations:- Monoceros- The Unicorn, Cancer- The Crab and Hydra- The Water Snake. The bad news is that they lack an abundance of bright stars. However it is easy to know where to look for Monoceros because it is in the middle of the Winter Triangle, bathed in the brightness of the Milky Way. Its brightest star is barely magnitude 4 so to the unaided eye this constellation doesn’t provide very much so we will move on.
The constellation of Cancer is one of the zodiacal constellations so needs a mention. It is the faintest of them and is fairly easy to find lying between Gemini and Leo and forming a triangle with the stars Pollux and Procyon. It doesn’t have a particularly distinct pattern but it does have an open cluster, Praesepe, (marked on the chart with a red cross and also known as ‘the Beehive’) which contains about fifty young stars and covers an area the equivalent of three full moons and being in a dark area away from the Milky Way it provides a hazy glow to the unaided eye in good conditions. You will need a pair of binoculars to resolve the individual stars.
Finally, Hydra- The Water Snake is the longest of the constellations and stretches about one quarter of the way around the sky with its head in the northern hemisphere and its tail in the southern hemisphere. It is difficult to trace out the chain of relatively faint stars but the six stars forming its head are more conspicuous. The brightest star, Alphard, representing the heart of the snake, is of magnitude 2 and lies alone in a blank region of the sky so is easier to spot on a line from Betelgeuse to just below Procyon and extended about the same distance again. Let’s hope for some really clear skies so that some of these dimmer objects stand out.
Something to look out for
There is a New Moon on the 11th February so an opportunity for dark skies in the middle of the month. You may also care to look out for the waxing crescent Moon on the following days to the WSW just after sunset. Mars is now in Aries and has a close approach with the Moon on the 19th February. The pair will be visible from 6.00pm onwards above your southern horizon with the Moon passing 3.5 degrees (7 Moon diameters) to the south of Mars after 10.00pm. before sinking towards the horizon and setting after midnight. Of course throughout the month you can continue to enjoy Orion, The Winter Hexagon and the Winter Triangle.