The night sky (local astronomy)
January Night Sky
Heavens above - January 2008
As the New Year dawns, Mars is the brightest object in the evening sky. It is in the sky as darkness falls and shines all night on the border between Gemini the twins and Taurus the bull. On the evening of 19/20th January, Mars appears to skim past the waxing gibbous Moon’s limb, coming closest just after midnight. Venus still shines brightly in the pre-dawn skies, joined by Jupiter in the last week of January. Venus is currently moving away from the Earth and is shrinking rapidly in the telescope. Saturn rises with Leo around ten O’clock in the eastern sky and is on view all night long. It is truly spectacular at the moment with the axial tilt just 7 degrees. This means the rings as viewed from Earth are almost edge-on and Saturn’s South Pole is angled towards Earth at present. On the early morning of 25th January a bright gibbous Moon will appear to pass very close to the ringed planet. The Earth reaches its closest approach to the Sun on 4th January – known as the perihelion. This seems to be counter-intuitive – how can the Earth be closest to the Sun in the middle of winter? – but of course the seasons are caused by the axial tilt of the Earth’s axis and the actual distance from the Sun plays a very small part in the temperature changes associated with the seasonal variation.
The winter constellations are now at their best with Orion and his retinue high in the south. In hot pursuit of Orion are his faithful hunting dogs - Canis Major (The Great Dog), with brilliant, sparkling Sirius - the brightest star in the sky - and also by Canis Minor (The Little Dog) with its own first magnitude star Procyon. Sirius is almost due south at midnight during January and it sparkles constantly just above the horizon. Above Orion and to the southeast is Gemini, with its twin stars Castor and Pollox. Bright Capella, the principal star in Auriga the charioteer lies in the zenith at this time, high overhead. Clear, dark locations with a moonless sky will allow views of the winter Milky Way as it sparkles overhead in Perseus, flowing down to the southern horizon past Orion. This is a fine area to sweep with binoculars as the region contains many open star clusters which mark out the main disk of our own star city - the Milky Way galaxy. The little star cluster known as the Beehive in Cancer the crab lies almost overhead these evenings and on 22nd of January around nine O’clock, the Moon makes its way through the cluster, gradually obscuring the tiny stars of the cluster. The Moon will be almost full and binoculars will show the whole event to best effect.
The opening days of January host one of the annual meteor showers, the Quadrantids. Named after a now defunct constellation, Quadrans Muralis, the meteors will show maximum activity, likely to be 20 or so meteors per hour, on the evenings of 3rd and 4th January. Comet Holmes continues to shine after its spectacular naked eye outburst back in October. Although its apparent size is now much greater than the full Moon, clear, dark skies will be needed to show the remnants of the dust ball as its microscopic particles disperse into the interstellar medium. Another comet has appeared in our skies – comet Tuttle – it is close to the Andromeda Nebula in the early days of January, and it is predicted to reach its maximum brightness around the 5th January.
The Irish Astronomical Association opens its 2006 lecture programme with a couple of members’ talks on observing and telescopes on the 9th of January. On the 23rd January Dr Paul Callanan from University College Cork will give a talk on ‘Photons from the Invisible’. Also worthy of note, on January 5th, the Association will hold our now annual Christmas and New Year Party at the Tudor Private Cinema in Comber - in past years these have been absolutely excellent fun evenings - full of food, film entertainment and prizes!
Any new (and very welcome!!) visitors to these meetings should note that they are free of charge and held in our new venue – the
Heavens Above is compiled for the Green Spectator by Andrew McCrea, immediate past-President of the Irish Astronomical Association (IAA). I would be delighted to answer readers’ questions on matters astronomical, telescopes, binoculars and the IAA either by post to the Spectator office or by telephone on Bangor (91) 273584 or via email on andrew@mccreaa.freeserve.co.uk, website http://www.mccreaa.freeserve.co.uk.