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.
Optic GSO RC12 Truss - Aperture 304mm, focal lenght 2432mm, f/8
Mount 10Micron GM2000 HPSII
Camera ZWO ASI 2600 MM Pro with filter wheel 7 positions
Filters Astrodon Gen2 E-Serie Tru-Balance 50mm unmounted RGB
Guiding system ZWO OAG-L with guide camera ASI 174MM Mini
Exposure details R 12x300" bin3 -15C
G 12x300" bin3 -15C
B 12x300" bin3 -15C
Total integration 3h
Acquisition Voyager, PHD2
Processing Pixinsight 1.8, Photoshop CS5, NoiseXTerminator, BlurXTerminator
Location Promiod (Aosta Valley, Italy), own remote observatory
Date 10 February 2023