Abstract:
Photoelectric magnitudes and colours in the UBV system have been determined for 73 stars in NGC 581. The value of the interstellar reddening is 0 ͫ . 38. The distance modulus to the cluster is estimated at 12 ͫ .16±0 ͫ .1 and an age of 4 x 10⁷ years is ascribed. The cluster luminosity function is compared with the general and initial luminosity functions.