The bright star SAO28064 in Ursa Major in the center of this image is shining at glaring mag 5.63 intensity, yet it is hiding a very faint jewel: a large but faint spiral galaxy NGC 3733, situated just 4 arc-minutes left from this dying giant star. It is mixing its blueish light travelling 55 million years through space with the young photons sent from the star just 411 years ago. The surface brightness of NGC 3733 is 23.5 mag per square arc-seconds and it belongs to the class of low surface brightness (LSB) galaxies. 5″ to the lower left side of NGC 3733 you can see the compact edge-on galaxy NGC 3737 and it is probably part of cluster Abell 1318. This cluster is part of the Ursa Major supercluster, situated at a distance of approx. 780 million light years. You can see a lot of other faint and very distant galaxies in the bottom left corner, also belonging to this supercluster. NGC 3733 is playing hide and seek with his nearby friends NGC 3738 and NGC 3756 on the right.
NGC 3733, 3738 & 3758
Telescope: 16″ f3.75 Dream Scope
Camera: FLI ML16803
Mount: ASA DDM85
Exposure: 8 hours (54x300s L + 3x14x300s RGB)
Date: February 2020
Location: Southern Alps, France