M35: Open Cluster in Gemini
Open cluster in Gemini
Season Visible in Evening
Winter; November – April
Large bright open cluster in Gemini. Several hundred stars – around a hundred visible in a small scope. Compare to the nearby M37
Open clusters are easy to find and observe in small telescopes, pretty, and scientifically important. This is a group of stars all born from a common cloud of gas and dust. Since they came from the same gas cloud they are, astronomically speaking, all about the same age and all about the same distance from us, and they all started with about the same chemical composition. Knowing that they are the same age and at the same distance, the fact that they have different appearances allows us to learn a great deal about stellar evolution – the different appearances can only be a result of the different masses of the different stars.
Like many of the other winter open clusters, start by finding Orion in the southern sky. Orion is easy to find by looking for his distinctive 3-star belt.
Study Orion and the area around him for a moment.
Note the distance between his left foot and his left shoulder – we will use that as a measure.
Mentally extend that line in the same direction, the same distance.
Note that you end up just above and to the right of a pair of dim stars. (These are part of the foot of Castor, one of the Gemini twins.)
Point your telescope to the left of the end of your imaginary line. The distance to the left is about the same as the distance between two stars in Orion’s belt.
Go back to the picture with no lines, above, and do this mental test yourself, then compare your results to this target.
In your magnifying finder, you will find M35 as a small fuzzy patch of light.
(If you don’t have a magnifying finder, hunt around with your telescope, with your lowest-power, widest-field eyepiece.)
This simulation shows the appearance of this cluster in a 100 mm refractor with dark skies, at about 35x magnification. Note the interesting internal structures that the density and location of the stars seem to trace out.
All the above images were generated with Starry Night Pro.