M37: Open Cluster in Auriga

  Catalogues M37; NGC 2099
  Names Open cluster in Auriga
  Type Open Cluster
  Constellation Auriga
  Season Visible in Evening Winter; November - May
  Conversation Notes Brightest of the several open clusters in Auriga. Several hundred stars - around a hundred visible in a small scope. Compare to the nearby M38 and M35.

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. 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.

Finding M37

In mid-winter, look to the South, fairly high in the sky, for the constellation Orion. Southern winter sky, showing Orion and area above it
The constellation is easy to find by the distinctive line of 3 close-spaced stars. Southern winter sky, constellation Orion circled
The stars are the belt of Orion, a mythical hunter. Find his shoulders, feet, and head too. Constellation Orion, showing connecting lines
Now look straight above Orion's head, a distance about equal to his height, for a pentagon of stars. The top star in this pentagon, Capella, is very bright. Orion, bright stars of Auriga circled above it
The pentagon is part of the constellation Auriga. Constellations Orion and Auriga, each showing their connecting lines

Trace the line across the bottom two stars in the pentagon, and point your telescope just outside this line, slightly to the left of its centre.

If you have a Telrad, the outer circle should just touch the line.

Auriga, showing telescope pointed outside the middle of the bottom-left edge

In a magnified finder, the cluster should be just visible as a small fuzzy patch of light.

If you don't have a magnifying finder, hunt around carefully with your telescope, fitted with its widest-field eyepiece.

Image of m37 in an 8x finder
In a telescope with an eyepiece giving 30x - 50x magnification you should be able to resolve individual stars and note their varying brightness and colour. Image of M37 in telescope at about 30x magnification

All the above images were generated with Starry Night Pro.


 
  166  accesses changed Feb 23, 2008
 
 
Copyright © 2008 Richard McDonald