IC 166 (Tombaugh 3) is a trumpler (https://en.wikipedia.org/wiki/Trumpler_classification) class II 1 r open cluster approximately 16,600 light-years away in Cassiopeia.
Luminance – 25x300s – binned 1x1 – 125 minutes
RGB – 12:8:8x180s – 36:24:24 minutes each – binned 2x2
209 minutes total exposure – 3 hours 29 minutes
Imaged August 27th, 29th, 30th and 31st, 2022 from Dark Sky New Mexico at Rancho Hidalgo (Animas, New Mexico) with a SBIG STF-8300M on an Astro-Tech AT12RCT at f/8 2432mm.
LRGB - https://www.flickr.com/photos/dcrowson/52381102616/sizes/l/