Berkeley 51 is a trumpler (https://en.wikipedia.org/wiki/Trumpler_classification) class III 3 p open cluster approximately 6-12,000 light-years away in Cygnus.
PN K 3-57 (PN G072.1+00.1, PK 072+00 1 and others) is a planetary below center near the left edge of the image. This one looks like an odd-colored, blobby star.
Luminance – 24x300s – binned 1x1 – 120 minutes
RGB – 8x180s – 24 minutes each – binned 2x2
182 minutes total exposure – 3 hours 2 minutes
Imaged August 29th, 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/52328040873/sizes/l/