A busy morning sky
WHEN: From 13 December onwards
There’s an interesting gathering in the early morning sky of two bright planets, the Moon, an asteroid and two comets. The planets in question are Jupiter and Mars, both of which can be seen in the pre-dawn sky from the start of December onwards, and the asteroid is Vesta. It’s moving on a path to the north of Jupiter and remains at 8th magnitude all month, so you’ll need at least a pair of binoculars to see it. The asteroid is best positioned from the middle of the month onwards, when it will have crept away from the morning twilight and can be seen against the darkest skies.
Fifteenth-magnitude comet P/2010 H2 Vales is probably better suited for astrophotography. The comet is interesting because it appears to keep track with Vesta, travelling along a parallel path just north of the asteroid. It is best seen from 17 December onwards, when it will be able to reach a higher position against a darker sky. Mag. +10.4 comet 24P/ Schaumasse can also be seen in the vicinity, higher in the sky passing through Virgo.
Between 13-16 December, a waning crescent Moon joins the party, forming an attractive arrangement with Jupiter and Mars. The presence of the Moon will make it hard to find comet 24P/ Schaumasse or photograph faint comet P/2010 H2 Vales, and we would recommend waiting for it to clear the area before making an attempt. Any morning after 16 December from around 06:00 UT should be fine.
Mars and Jupiter appear to converge towards the end of the month, ahead of a very close encounter during the first week of January 2018. The planets appear separated by 24 arcminutes on the morning of 6 January and by just 14 arcminutes on 7 January.
Object positions correct for 06:00 UT on the dates shown; sky position correct relative to the horizon for mid-December