M 103 is an open cluster in Cassiopeia, discovered by Mechain in 1781 and this was the last object that Messier included in his original catalog. This is a rich cluster, with 172 confirmed members, and it is a relatively young cluster, about 25 million years.
Additional Information
Object
Name(s): M 103. NGC 581
Type: Open Cluster
RA: 01h 33m 23s
Dec: +60° 38’ 53”
Constellation: Cassiopeia
Size (arcmin): 6×6
Magnitude: +7.4
Distance: 10,000 ly
Image
Date: 2012-10-15
Location: Corbera de Llobregat, Barcelona, Catalonia
Size (arcmin): 14×10
Telescope: Celestron 11” HD f/10
Camera: FLI ML6303 (3072x2048pix)
Guiding: Orion SSAG/Nikkor 500mm f/8
Total exposure: 11 min
Processing: CCDStack, Photoshop CC 2016 and PixInsight