Nova Circini 1987

S. A. Ilovaisky, Observatoire de Haute Provence; H. Pedersen, European Southern Observatory; and M. van der Klis, EXOSAT Observatory, report: "Analysis of CCD photometry of the optical counterpart of the Ginga x-ray nova 1354-64 (Pedersen et al., IAUC 4357), obtained with the Danish 1.54-m telescope at La Silla between Mar. 29 and Apr. 1, reveals that the brightness variations we observed are consistent with a 46-hr periodic modulation of 0.3-0.4 mag amplitude in V and a secular decrease in brightness by 0.04 mag/day. Further observations obtained during the following week with the 1.54-m and ESO 3.6-m telescopes show that the brightness decrease has probably steepened. Our last measurement on Apr. 7 UT gives V = 17.5. Further spectroscopic observations with the ESO 3.6-m telescope on Apr. 6 and 7 show the appearance of H-alpha and H-beta in emission. Observers are urged to monitor the object."