NGC2394 and NGC2355 – these two open clusters are not very impressive. But they have their own stories. First one is not proved to be cluster at all. Second one is very old and was discovered more than once.
Do you know any object in Canis Minor (Little Dog) constellation? Procyon star, of course! And deeps sky object? Hmm, not really… unless you mean NGC2394. This is small bunch of stars, probably open cluster. It lies about 3,000 light years away. It was discovered by William Herschel in December, 1785. Picture below was made with Meade ACF 10″ telescope and QHY163M camera. It is RGB composite, 45 minutes of total exposure with RGB filters.
And second open cluster is NGC2355 (or 2356) – old open cluster in Gemini. Its age is estimated for one billion years – it is pretty much for open cluster. It is placed about 7,200 light years away. It was discovered by William Herschel probably on March, 8th, 1784, but the noted coordinates are not accurate, and at that place there is no cluster in the sky. Herschel probably made a mistake, and observed this cluster again on March, 16th, and noted it down as different object. When John Dreyer has been creating NGC catalogue, he put these both observations as different objects – so we have both 2355 and 2356. Image below was made again with ACF 10″ telescope and QHY163M camera. Total exposure time was 120 minutes with LRGB filters.
Clear skies!
