Deep Sky Object in Summer
M7 (OpenCluster in Scorpius)
|Date & Time: ||Aug 8 1999, 21:45 JST(+0900), 20min. Exp.
|Optical: ||TAKAHASHI 16cm(6.3") epsilon (f=530mm, F3.3)
|Auto-guided with TAKAHASHI EM-200 Equatorial
|Camera: ||VIXEN VX-1
|Film: ||Ektachrome E200 (+1EV pushed)
|Location: ||Koumi town, Nagano pref.
M7 (NGC6475) is clearly the best open cluster of the constellation.
This magnificent object is extremely large (about a size of 1 degree) and quite bright,
being visible even to the naked eye at a viewpoint far from urban area.
You will be impressed the splendid scenery of about 50 stars scattered in the Milky Way with binoculars.
|M7 (NGC6475) / Open Cluster, type e|
|R.A.||17h 53m 54.0s (2000.0)|
|Dec.||-34° 49' 00" (2000.0)|
|Real Size||22 light yrs.|
|Distance||1230 light yrs.|
In fact, in the Messier's catalogue, M7 is positioned at the southest point in the sphere,
the culminate latitude of that is only about 20 degrees at Tokyo.
And M7 is one of rare objects known before the telescope was invented,
the cluster was found out by an ancient astronomer Ptolemy in 2nd century.
This cluster has another name of "Ptolemy's Cluster".