Messier 35 (Gemini)

Fig. 1 - Perfectly filled with brilliant stars, of exquisite beauty: The open cluster Messier 35 in Gemini, photographed with an 8-inch f/5 Newtonian reflector on a ZWO AM5 mount. Directly southwest of Messier 35 (in the image to the right of Messier 35) is the very compact open cluster NGC 2158.

Object name:	Constellation:	Coordinates:	Apparent size:	Visual brightness:
Messier 35 (NGC2168)	Gemini	06h09m / +24°20'	28'	5.1 mag
NGC2158	Gemini	06h07m / +24°06'	5'	8.6 mag

The open cluster Messier 35 (NGC 2168, "Shoe-Buckle Cluster") in the constellation Gemini. The cluster with an estimated age of 100 million years contains 305 stars that are extremely likely members and up to 4,349 stars with 50% membership probability. Messier 35 is approximately 3,000 light-years from Earth.

There is an attractive contrast in size and star density to the star cluster NGC 2158, which is only 0.4' to the southwest and therefore in the same field of view. NGC 2158 is five times further away, but has at least ten times more stars and is much older. Messier 35 was discovered by the Swiss astronomer Philippe Loys de Chéseaux in 1745 and indepentently discovered by the English medical doctor and astronomer John Bevis before 1750. NGC 2158 was discovered by German-British astronomer William Herschel in 1784 (source: Wikipedia).

Exposure time: 3h 15min (65x3min) at gain 100 and -15°C, taken on January 4, 2025. Processing with Astro Pixel Processor (APP) and Photoshop. Darks, flats, bias and darkflats were used. The night was a rather refreshing experience. 12 inch of snow, recurring fog and -14°C (7°F) created the right atmosphere for this image. The power for the cooler stayed at 0% most of the time.

Equipment: Cooled ASI 2600MC Pro camera, TeleVue Paracorr Type II coma corrector, 8" f/5 "ONTC" Newtonian telescope riding on a ZWO AM5 Strain Wave Mount, ZWO OAG-L off axis system, ASI 174MM Mini guide camera, ASIAIR Plus.

M81 NGC2264