About image
NGC 2158 is an open cluster in the constellation Gemini with size 6' and magnitude 8.6.
It is easily identifiable because it is less than half a degree from the better known and brighter M 35.
Its scarce luminosity is justified by the great distance at which it is located, equal to over 16,000 light years, in a peripheral position in the Milky Way, on the arm of the Swan: therefore it also appears strongly obscured by the interstellar dust that interposes itself along the line of sight.
It is a very ancient cluster, with an estimated age of more than 1 billion years.