About image
NGC 7789 is an open cluster in Cassiopea constellation.
It is a very rich and concentrated cluster, formed by several hundred components and with an apparent diameter of 25’; its distance is estimated to be around 7620 light years.
Its age is quite advanced, estimated at 1.7 billion years or slightly less.
Technical data
Optic Tecnosky Apo refractor LT 130-910 with Riccardi reducer 0.75x (focal lenght 692mm, f/5.3)
Mount Skywatcher EQ8
Camera Atik 4000 with Starlight Xpress external filter
wheel 5 positions
Filters Baader 50mm
unmounted RGB
Guiding system Artesky Ultraguide 70mm
Exposure details R 19x300" bin1 -20C
G 19x300" bin1 -20C
B 19x300" bin1 -20C
Total integration 4h45'
Acquisition Voyager, PHD2
Processing Pixinsight 1.8,
Photoshop CS5
SQM-L 18.5
Location Rescaldina (Italy), home terrace
Date 10/13/14 October 2021