Open star cluster M35 is consisted of several hundred stars scattered over the area covered by the full Moon. At its distance of 2,800 light years, this corresponds to a linear diameter of about 24 light years;. With about 100 million years, it is of intermediate age, and contains some post-main sequence stars.
Even the naked eye finds this cluster easily near the 3 "foot stars" of Gemini under fairly good observing conditions. The slightest optical instrument will resolve the brighter stars and make it a splendid view at low magnifications, a nearly circular cluster with rather uniform stellar distribution. In telescopes, low powers and wide-field eye pieces show M35 at its best.
Amateurs with more powerful telescopes can view its fainter neighbor, NGC 2158 (at the lower right in this image); it is situated just about 15 arc minutes southwest of M35. NGC 2158, of about mag 8.6 and about 5 arc minutes angular diameter, contains many more stars, is much more compact, over 10 times older and over five times more remote than M35, and because it consists of older stars, its light is dominated by yellower stars. Because of these properties, NGC 2158 was once even taken for a globular cluster candidate.
Image taken with a Canon EOS 20Da camera in prime focus of a professional reflector-telescope at 1290mm f/5.1. Exposure time is 90 minutes !
This is a very deep and real image, so the "noise" in background is no noise, these are very very dim stars again. The image is not overprocessed and sharp. See the spikes on the very bright stars.