Open cluster M35

About the object

Open cluster M35 in Gemini, a few hundred stars over an area the size of the full Moon, about a hundred and fifty million years old. In the same field sits NGC 2158: a much older and denser cluster several times farther away, which therefore looks like a small fuzzy knot. The pair in one frame shows nicely how distance changes the look of similar objects.

Distance: about 2,800 light-years, apparent size in the sky: ≈ 28′, constellation Gemini.

How it was shot

Everything here was shot with a DWARF Mini smart telescope from a balcony in a city in Ukraine: light-polluted sky, only the eastern half of it visible, and a roof overhang that cuts off the south. 2 nights (all in September), 2 sessions, 312 frames with exposures of 30 s, without a filter, in broadband. The stack holds 1 h 56 min of light; the longest night, 2 September, gave 1 h 30 min. The goal for this object is 1 h, and it is reached. First night 2 September 2026, last one 3 September 2026.

Open cluster M35 in the night log: 1 September, 2 September.

How it went

Two nights of thirty-second frames without a filter. The main interest in the frame is not M35 itself but the tiny NGC 2158 beside it: in a city sky it barely stands out from the background, and it alone was worth giving the cluster a second night. Both are visible in one field; the goal for bright clusters is reached.