HST IMAGES OF THE ECLIPSING PULSAR B1957+20

We have obtained images of the eclipsing pulsar binary PSR B1957+20 us ing the Planetary Camera of the Hubble Space Telescope. The high spati al resolution of this instrument has allowed us to separate the pulsar system from a nearby background star which has confounded ground-base d observations of this system near optical minimum. Our images limit t he temperature of the backside of the companion to T less than or simi lar to 2800 K, about a factor of 2 less than the average temperature o f the side of the companion facing the pulsar, and provide a marginal detection of the companion at optical minimum. The magnitude of this d etection is consistent with previous work which suggests that the comp anion nearly fills its Roche lobe and is supported through tidal dissi pation.