BBC Sky at Night Magazine
Comet C/2017 T2 PanSTARRS shines bright
BEST TIME TO SEE: Nights of 19/20 and 20/21 May
It may not have reached naked-eye visibility as originally forecast and it may not have been the most spectacular of comets, but C/2017 T2 PanSTARRS has been a steady performer and well placed in UK skies. As well as passing through peak brightness this month, the comet passes close to a pair of galaxies in Ursa Major, M81 and M82 – Bode’s Galaxy and the Cigar Galaxy.
It begins the month at an estimated mag. +11.6 in Camelopardalis. Not the easiest constellation to identify nor navigate, the comet passes close to mag. +4.6 TYC 4530-2010-1 on the night of 4/5 May, heading east towards the northern border of Camelopardalis with Ursa Major. It crosses on the night of 17/18 May, a time when it’ll be close to the 11th magnitude galaxy IC 529. It continues southeast, passing close to mag. +5.2, 27 Ursae Majoris on the nights of 19/20 and 20/21 May, as it approaches M81 and M82. The comet’s closest approach to the galaxy pair occurs on the nights of 22/23 and 23/24 May. It’s expected to be mag. +11.5. The galaxies are listed at mag. +7.0 for M81 and +8.6 for M82.
Tracking southeast, it passes close to IC 2574, a 10th magnitude dwarf galaxy. During May, it should be visible in a small scope. It appears small if you plan to image it.
The comet’s brightness is estimated to stay above mag. +12 until July 2020.