Trumpler 21

Number of stars per data source

	Reference   82 :    3 stars
	Reference  470 :    2 stars

References

 82

Moffat A.F.J., Vogt N.

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

Southern open star clusters III. UBV Hbeta photometry of 28 clusters between galactic longitudes 297 and 353

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

 470

Knude J.

(1992) Astron. Astrophys. Suppl. 92, 841

uvby Beta observations of 528 type B stars with V between the 8th and 9th magnitude

1992A&AS...92..841K