Asterisms – David’s D, Collinder 21

By: Steve Goldberg

Asterism: a grouping of stars that form a recognizable pattern.
Constellation: Triangulum
Right Ascension:  01h 50m 09.6s
Declination: +27° 06' 54"
Magnitude: 8 to 10
This month’s asterism is called David’s D. But technically it is number 21 in the Collinder catalog of star cluster. It is located at the apex of the Triangulum constellation near Aires.




To locate this object, find stars Alpha α and Beta β Aries on the right in this picture. David’s D forms the top of a triangle, very similar to the constellation Triangulum.

The shape of the “D” can be seen here, with the “straight line” going from top to bottom in this picture with the “curved line” going around the circle to the right.


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