Caroline’s Discovery

NGC 659
Sketch and Details by Paul Mettam

CH 20 NGC 659
OPEN CLUSTER
CASSIOPEIA

12″ NEWTONIAN F5
X165
FIELD OF VIEW: 13′

12 / 12 / 2009
LONG EATON, DERBYSHIRE, ENGLAND.

GRAPHITE PENCIL, WHITE PAPER, INVERTED.

NOTES:

With Cassiopeia high overhead in the evening at this time of year it is a good time to view its many deep sky objects. This cluster, which is about 6′ of arc in diameter, was discovered by Caroline Herschel on September 27th 1783 and is number 20 on her list. Four magnitude 10 stars form a rectangle on the east side and about 30 magnitude 10 to 13 stars form chains to the west of this. A close double star lies near the centre. It is difficult to decide where the outer edge of the cluster lies as it is in a rich area.

This cluster is about 9200 light years away in the Perseus Spiral Arm and is around 35 million years old. It has been found to contain several fast spinning, giant, Be type variable stars.