NGC 581

Number of stars per data source

	Reference  290 :    1 star
	Reference  542 :    3 stars

290: Perry C.L., Johnston L.; (1982) Astrophys. J. Suppl. 50, 451; A photometric map of the local interstellar reddening within 300 parsecs; 1982ApJS...50..451P
542: Javakhishvili G.Sh., Salukvadze G.N.; (1996) Astrophysics 39, 3; uvby beta electrophotometry of the components of Trapezium multiple star systems; 1996Ap.....39....3J