[BAA-ebulletin 00603] Close encounter between Messier 71 and comet Garradd C/2009 P1

[BAA electronic bulletins service]

Observing Opportunity
A close encounter between Messier 71 and comet Garradd

Close encounters between different classes of astronomical object are always of interest, both for the visual observer and the imager.  Currently comet C/2009 P1 Garradd is in Sagitta and making a close approach (in line of sight terms only of course) to globular cluster Messier 71.

M71 is a very loose globular which is close to us and lacks the condensed core of some of the more familiar summer globulars. In small binoculars or telescopes it appears as a mag 8 misty patch around 6 arcmin diameter and looking very comet like in appearance.  It is easy to locate as it lies in Sagitta between and slightly south of a line from mag 3.5 gamma (the bright star forming the point of the arrow shape) and mag 3.8 delta just under 3 degree to the west. The position of M71 is RA 19h 54m 19s and Dec +18deg 49min (2000).

An ephemeris for Garradd can be found on the BAA Comet Section web page but for the night of August 26 / 27 is given as 19h 53.7m and Dec +18.57deg (2000)

Last night (Aug 24 / 25) under mag 5 skies both comet and cluster were easily visible together in hand held 10x50 binoculars, both appearing similar in magnitude and in size. In 15x70 binoculars (4 deg field) the cluster appeared round with the comet diffuse and fan shaped.


Stewart Moore
Director BAA Deep Sky Section