UBV PHOTOMETRY AND THE SPECTRUM OF FG-SAGITTAE IN 1996-1997

The UBV observations of FG Sge in 1992-1997, which were corrected for the contribution of the companion and the nebula, are presented. The b rightness distribution over the planetary nebula He 1-5 was measured i n the H alpha line. A ring structure of the nebula was detected. A tot al of five R CrB-type minima have been observed in FG Sge since 1992, with the deepest minimum being in 1996. The star exhibited a dramatic bluing on the descent to some minima. In 1997, pulsations with a perio d of similar to 115 days were observed in the bright state. The epochs of pulsation minima and profound R CrB-type dimmings were found to fi t the same photometric elements. Low-resolution spectroscopic observat ions of the star show that the intensity of the Swan bands varies with pulsation phase. In the summer of 1996 the Na I lines in its spectrum were in emission. In the classification of carbon stars, the spectral type of FG Sge in 1996-1997 is estimated to be C1,1-C1,2, and, accord ingly, its temperature is 4600-4800 K.