Trumpler 21

Number of stars per data source

	Reference  444 :   17 stars
	Reference  600 :   24 stars

References

 444

Moffat A.F.J., Vogt N.

(1973) Astron. Astrophys. Suppl. 10, 135

Southern open stars clusters. III. UBV-Hbeta photometry of 28 clusters between galactic longitude 297 and 353

1973A&AS...10..135M

 600

Peterson C.J., Fitzgerald M.P.

(1988) Monthly Notices Roy. Astron. Soc. 235, 1439

UBV photometry in four southern open clusters with suspected supernova remnants

1988MNRAS.235.1439P