Night Sky Watch for December

Written by David Pugh

Dear Colleagues, Wishing you all a Happy New Year. We certainly need it!

So, what is happening in the night sky this month? Well, after the Great Conjunction of Jupiter and Saturn on Dec 21st, the two gas giant planets can only be seen low in the SW immediately after sunset before they disappear below our horizon. Little Mercury reaches greatest elongation east of the Sun on Jan 24th about 5pm low in Capricornus after sunset not far east of Jupiter. Brilliant Venus still puts on a splendid pre-dawn display in the east in Sagittarius in the first week of January.

Mars, the red planet, is still well placed in Aries at the start of the month, reaching its highest position, due south, around 7pm at mag -0.2 and a disc size of 10.4". It lies 7.3 degrees from the first quarter Moon on the 20th. Uranus,at mag 5.7, can be viewed in binoculars in southern Aries. It is close to both Mars and the Moon on the 21st and its tiny blue-green disc can be viewed telescopically. Neptune, at mag 7.9 is difficult this month as its tiny blue disc lies in Aquarius and will have to be viewed straight after sunset in twilight conditions.

The Quadrantids Meteor Shower is perhaps the highlight of the month peaking about 2.30am tomorrow morning so the best nights to observe them, if clear, are tonight and tomorrow night (Jan 2nd and 3rd). However, it is totally cloudy at present (11pm) so tonight looks a non starter. Maybe tomorrow night. The Quadrantids are swift meteors usually with a narrow peak of strong activity lasting about 6 hours. Unfortunately glare from the waning gibbous Moon is likely to drown out all but the brightest meteors. The name of this shower comes from the defunct small constellation Quadrans Muralis (the Mural Quadrant) which is now in Northern Bootes so the meteors will appear to radiate from that part of the sky, not far from the end of the tail of the Plough. As for the Geminids last month, the advice is to observe with the naked eye the area of sky about 30 - 40 degrees either side of the radiant and about 50 degrees high for hopefully the best success. Good luck!

As for the deep sky, we are now very much into the winter constellations. Orion the Hunter looks glorious if it is clear, shining brightly at its highest, due south, by 10.30pm at the start of the month and 8.45pm by the end of January. Enjoy the most popular of all deep sky objects, the stunning Orion Nebula M.42 & 43, in Orion's "sword", below the 3 belt stars Alnilam, Alnitak & Mintaka. After the great pleasure of taking in the whole nebula with low powers, if conditions are favourable, take a closer look at the core of the nebula with a higher power eyepiece. Homing in on the famous small cluster the Trapezium take a close look at the fascinating Huygenian region that surrounds them and dark protruding nebula the "Fish's Mouth". Another interesting, though fainter object in Orion is the reflection nebula M78. You could also try for the Flame Nebula NGC 2024 immediately to the east of Alnitak the eastern star of Orion's Belt. However, to have any chance at all on this you will need to place Alnitak outside of the field of view else its glare will swamp the nebula. Unfortunately the nearby famous Horsehead Nebula B.33 requires both a large scope, a Hydrogen Beta filter and very dark skies. I have imaged it but never seen it visually.

You are really spoilt for choice on objects to view at this time of year but the problem in the UK is often getting a suitable moonless clear night and without too much wind. A few other suggested worthwhile objects include the famous Crab Nebula supernova remnant M1 in Taurus, the very bright cluster the Pleiades M45 great in binoculars or a small scope, and the rich cluster M35 in Gemini.

Good hunting and fingers crossed for some clear nights.

All the Best