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We present results (preliminary at this writing) from far UV images of the field containing SN~1987A and its light echoes. Long exposures were obtained in identical bands (B1: 1290-1830\AA\ and B5: 1455-1820\AA, 10\% power points) on both Astro missions, separated by 4.3 years. This allows stars and nebulosity to be almost perfectly subtracted in the differences between these exposures, while the light echoes, having moved by 25 to 95 arcsec, should remain visible. For reasonable models of the reflectance of the dust, and for published theoretical estimates of the far UV fluence from shock breakout through the progenitor star's surface, a far UV echo signal should be easily detected. Preliminary results indicate that this is not the case.
The optical echo from the same dust, as seen in the reflection of the maximum light pulse that occurred 80 days later, will allow us to determine the position where the far UV echo should have been detected, permitting an even more sensitive measurement. By the time this work is presented, we plan to have obtained and analyzed this 80-day-delay image, and intend to report a sensitive upper limit or measurement. The implications of this result to dust UV reflectance models or shock breakout fluence predictions will be discussed.
