NGC 2506

Number of stars per data source

	Reference   20 :   15 stars
	Reference   27 :   28 stars

20: Geisler D.; (1987) Astron. J. 94, 84; Washington photometry of open cluster giants: Seven metal-poor anticenter clusters; 1987AJ.....94...84G
27: Geisler D., Claria J.J., Minnitti D.; (1992) Astron. J. 104, 1892; Washington photometry of open cluster giants: nine old disk clusters in the third galactic quadrant; 1992AJ....104.1892G