Messier/type:M103 / Open cluster
mag/dia/dist:7.4 / 6' / 8,130 ly
constellation:Cassiopeia
date/time/place:Sep 15, 01 / 03:00 / Bangkok
trans'y/seeing/l-poll:good / good / low
telescope:newtonian 4.5", f 8.8
eyepieces/power:10mm / 100x
sky atlas page:1
Start from one leg of w-shape of Cassiopia, hop to star 37 & 39. Star37, 39 and star mag7 form as right angle triangle. Star mag7 at the right angle is double star, can be seen in finder scope, M103 locates at the same position. At eyepiece, using 10mm (100x) is better than 25mm (40x). Four dim stars lie between double star and another four stars on the north (top of my sketch). After check in text, M103 is the lower one.

Refer to text: 25 stars detached no concentration, Max mag10.6 , Arrowhead shape, extends 15 ly, age 220 million years. Home
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