If we are fortunate, Comet Ison (C2012 / S1) may put on quite a show in the December skies. Right now, the comet is approaching the inner solar system from quite a high angle above the north poles of the Sun, earth and most other planets (Uranus does its own thing by rolling along poles generally pointed in the same directions as the orbital plane).
Comet ISON is expected to hurtle very close to the Sun’s south pole around 28 November and then emerge into a more visible position on the earth’s side of the solar system, heading back into the north (which means above the Sun’s north pole) all through December. At some point early in the month, we’ll know if it survived that close encounter intact, or broke apart, and just how bright it becomes. Some estimates continue to promise a very bright object even brighter than Venus and considerably brighter than Jupiter which will also be prominent in clear December skies. Our closest approach to the comet is 26 December (0.42 A.U.) at which time it will be about the same distance from the Sun as is the earth (1 A.U.). If it is a bright object, Comet ISON should have a long tail pointing up away from the Sun and towards the pole star (Polaris) which it will be aiming towards on its exit from our solar system. By January, a much less prominent comet would be only viewable in binoculars but the earth will go through the remnants of its tail which might produce a minor episode of shooting stars or meteors.
So it’s fingers crossed that Comet ISON will produce unlike some other hyped comets of past decades, and put on a glorious show in December. Then there’s the matter of finding clear enough skies in the cloudiest month of the year in many locations around the northern hemisphere.
To see an orbit diagram for Comet ISON, go to this link: