NGC 2506

Number of stars per data source

	Reference   11 :  195 stars
	Reference   85 :  801 stars

References

 11
Purgathofer A.
(1964) Ann. Univ. Sternw. Wien 26 no 2
Dreifarben Photometrie in offenen Sternhaufen sowie in zwei Sternfelden in Cygnus
 85
McClure R.D., Twarog B.A., Forrester W.T.
(1981) Astrophys. J. 243, 841
The old open cluster NGC 2506 and its similarity to NGC 2420
1981ApJ...243..841M