At the evening of Nov 10, 2000, the AIP students Robert Schwarz and Andreas Staude directed the 70 cm telescope on the roof of the main building towards the field of HS0455+83. Soon after start of the observations, performed with short integrations of 30 secs only, the star's brightness changed dramatically. A binary eclipse was discovered. A second eclipse could be observed in the same night despite large transparency and sky brightness variations (third and fourth panel from above). The reduced light curve of the binary, cleaned from atmospheric effects is shown in the left figure top panel, that of a comparison star in the field in the second panel. The right figure shows the phase-averaged light curve. The eclipses allowed a precise determination of the orbital period of only 3.6 hours. (credit: A. Schwope)
more at http://www.aip.de/~ast/70cm/70cm.html  (image added 2002-12-05)