Messier 103 (M 103)

Introduction | Map | Find/Identify | My Own Photos | My Own Observations | References

On this page I collect my observations of the open star cluster M 103 in the constellation Cassiopeia.



To Stoyan's surprise, the open star cluster M 103 in the constellation Cassiopeia has made it into Messier's list as the only star cluster of the impressive stellar field in the Cassiopeia constellation (M 103, NGC 457, NGC 654, NGC 663). But actually it looks more like a small asterism of 3-4 stars - at least in my telescopes. In the eVscope it looks richer...

Size: 6' (Stoyan)
Distance: 7,200 light years (Stoyan)
Rating: *** (Stoyan)



M 103, to the left of it NGC 654 and NGC 663, to the right of it NGC 457 (Owl Cluster). For orientation purposes, the Andromeda Galaxy M 31 is included in the map, as well as the Perseus double cluster NGC 884/869 and avove it St 2, which, according to Stoyan, is a "must" for small telescopes. (Image Courtesy of SkySafari Astronomy,



Find: The open star cluster M 103 is located a little bit below the connecting line between the two stars Segin und Ruchbah in constellation Cassiopeia. Seen from Ruchbah, the star to the right, M 103 is located at about 1/5 of the total distance.

Identify: M 103 in the constellation Cassiopeia is somewhat hard to identify for me. Typically, I can see only a few stars, which are hard for me to recognize as a cluster at all. Below is the view in SkySafari:

(Images Courtesy of SkySafari Astronomy,


My Own Photos



M 103 - Feb 15, 2020

  M 103 - Mar 18, 2020   M 103 - Mar 18, 2020, processed
M 103 - Sep 7, 2020   M 103 - Sep 7, 2020, processed    

eVscope 2


M 103 - Nov 2, 2022


M 103 - Nov 2, 2022, processed



M 103ff, Nov 1, 2022 - original (365 frames = 3650 seconds)

  Evaluation by


My Own Observations

Observations Summer to Autumn 2016

Observations September/October 2018

Observations September/October 2019

Observations January 2020

Observations February/March 2020

Observations September 2020

Observations November 2022



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