Optical observations of the recurrent nova associated with A0620--00: 1917--1975

A previous outburst of the eruptive star associated with the transient X-ray source A0620-00, first detected in 1975 August, has been discovered on Harvard plates taken in 1917. We present the light curve of the earlier event and conclude that this star is a typical recurrent nova with an absolute magnitude M/sub V/=-5.9+-0.5 at maximum brightness. The A0620-00 star has no detectable proper motion, and there appears to be little interstellar absorption. Our best estimate of its distance is 11+-3 kpc. A0620-00 is only 30.60 from the direction of the galactic anticenter, and therefore must be located well beyond the detectable limits of our Galaxy