Czernik 2

Number of stars per data source

	Reference  117 : 2351 stars
	Reference  509 : 13588 stars

117: Phelps R.L., Janes K.A.; (1996) Astron. J. 111, 1604; The old open cluster, Berkeley 66; 1996AJ....111.1604P
509: Maciejewski G., Niedzielski A.; (2008) Astron. Nachr. 329, 602; Photometric study of 9 doubtful open clusters; 2008AN....329..602M