NGC 147 (also known as DDO3 or Caldwell 17) is a dwarf spheroidal galaxy about 2.58 Mly away in the constellation Cassiopeia. NGC 147 is a member of the Local group of galaxies and a satellite galaxy of the Andromeda Galaxy (M31). It forms a physical pair with the nearby galaxy NGC 185, another remote satellite of M31. It was discovered by John Herschel in September 1829. Visually it is both fainter and slightly larger than NGC 185 (and therefore has a considerably lower surface brightness). This means that NGC 147 is more difficult to see than NGC 185, which is visible in small telescopes. In the Webb Society Deep-Sky Observer’s Handbook, the visual appearance of NGC 147 is described as follows: Large, quite faint, irregularly round; it brightens in the middle to a stellar nucleus. The membership of NGC 147 in the Local Group was confirmed by Walter Baade in 1944 when he was able to resolve the galaxy into individual stars with the 100-inch (2.5 m) telescope at Mount Wilson near Los Angeles.

Telescope: Astro Physics 175EDF f8.3
Mount: Astro Physics 3600GTO “El Capitan”
Camera: SBIG STT8300
Guider: Mini Borg 50 / SBIG STi

L: 48×10 mins = 480 mins, R: 30×10 mins = 300 mins, G: 27×10 mins = 270 mins, B: 25×10 mins = 250 mins

Total Imaging Time: 21h 40m

Data Imaged remotely over 8 nights during November 2021.
Data acquisition & Processing by David Churchill.

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