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Close encounter between Messier 71 and comet Garradd C/2009 P1

Over the next few nights the comet C/2009 P1 Garradd makes a close pass by of Messier object 71 in the constellation of Sagitta (the arrow). Close encounters between different classes of astronomical object are always of interest, both for the visual observer and the astronomical imager.

This chart shows the position of the comet and M71 in Sagitta around 22:30UT on August 26 2011.

Stewart Moore, director of the BAA Deep Sky Section writes:

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)

On Aug 24 / 25 under mag 5 skies both comet and cluster were easily visible together in hand held 10×50 binoculars, both appearing similar in magnitude and in size. In 15×70 binoculars (4 deg field) the cluster appeared round with the comet diffuse and fan shaped.

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