Open Cluster M103 (NGC 581), type 'd', in Cassiopeia
RA 01 : 33.2 (h:m); Declination +60 : 42 (deg:m); Distance 8500 light years;
Visual Brightness 7.4 (mag); Apparent Dimension 6.0 (arc min)
Open cluster M103 is one of the "latest additions" (together with M101 and 102) to his catalog, which Charles Messier included from Pierre Méchain's report, but had no occasion and no time to observe before publication.
Source and more: SEDS
October 9, 2008 20:02 - 20:39 UT.
Imaging: William Optics Zenithstar 80 ED II APO at f/6.8 [focal length 545 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 10x120s [1x1]; RGB: 5x60s [2x2], unguided.
September 20, 2006 21:24 - 21:32 UT.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm] and Baader Infra Red Blocking Filter.
Camera: Vesta Pro SC3a b/w RAW webcam, 41 autoguided exposures of 10 seconds.