COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 518 Konkoly Observatory Budapest 1971 February 14 HBV 477 A NEW ECLIPSING VARIABLE IN THE CYGNUS - CLOUD HBV 477 = BD + 29d3814 (9.5) Sp.: B0V M_V = -4.40 (Neckel, Th. Heidelberg Ver. Bd. 19, 1967) RA 19h52m39.28s D +29d43'31.2" (1900.0) HBV 477 was suspected to be an eclipsing variable by WACHMANN (unpublished) during his survey of the Cygnus- Cloud. All attempts to find the period of its light-changes failed. Therefore HBV 477 was put onto the program for photoelectric observations by the author and a total of 635 observations in B and V each was obtained from May 1969 until now. Once again it took a year and a half until the period could be found, because only ascending branches of the minima were observed and these showed a large scattering. The finally derived elements are together with their mean errors: Min.hel.= 244 0371.4095 + 1.95669202d . E +-14 +-72 Table I gives the times of minima, the epochs and the O-C. The observations starting JD = 244 0366 are photoelectric observations while the prior ones are photographic. Table I ------------------------------------------------------------------ O E O-C O E O-C ------------------------------------------------------------------ 2432775.465: -3882.0 -0.066 2440371.401 0.0 -0.009 3506.322 -3508.5 - .034 0372.359 + 0.5 -0.029 4133.479 -3188.0 + .004 0373.358 + 1.0 - .008 4234.474 -3187.5 + .020 0467.263 + 49.0 - .022 4626.548 -2936.0 - .014 0469.234 + 50.0 - .010 4827.595 -2935.5 + .055 0811.680 +225.0 + .015 4628.522 -2935.0 + .004 0812.658 +225.5 + .014 4829.583: -2934.5 + .066 0824.405 +231.5 + .021 5309.456 -2587.0 + .009 0825.379 +232.0 + .017 5360.310 -2561.0 - .011 0827.331 +233.0 + .012 2440366.493 - 2.5 - .025 0828.308 +233.5 + .011 0369.435 - 1.0 - .018 0875.273 +257.5 +0.015 0370.415 - 0.5 - .016 ------------------------------------------------------------------ The total of 422 photographic observations obtained by WACHMANN was reduced to one revolution by the above elements. Table II gives the normals formed out of these 422 observations, n giving the number of single observations for each normal. Table II ------------------------------------------------------------------------ Phase m_pg n Phase m_pg n Phase m_pg n ------------------------------------------------------------------------ 0.0221 10.41 12 0.4149 10.18 10 0.7587 10.15 7 .0449 10.37 10 .4445 10.29 11 .7828 10.12 9 .0786 10.20 8 .4733 10.34 8 .8009 10.10 11 .1067 10.23 8 .4945 10.40 11 .8155 10.10 8 .1204 10.13 12 .5165 10.33 11 .8292 10.14 9 .1465 10.15 11 .5331 10.35 9 .8436 10.17 10 .1755 10.14 14 .5655 10.26 10 .8693 10.18 11 .2080 10.17 11 .6035 10.18 9 .8910 10.14 9 .2310 10.15 8 .6311 10.15 9 .9123 10.20 9 .2619 10.11 10 .6467 10.12 10 .9337 10.15 7 .2895 10.14 9 .6941 10.19 8 .9547 10.34 8 .3074 10.17 10 .6821 10.14 10 .9873 10.46 7 .3276 10.14 10 .6989 10.14 9 .9819 10.35 6 .3453 10.19 12 .7131 10.12 11 0.9999 10.45 11 0.3776 10.20 11 0.7330 10.10 8 ------------------------------------------------------------------------ The mean light-curve is given in the figure. HBV 477 shows the following light-changes: Max I : 10.13m Min I : 10.47m II : 10.12m Min II : 10.40m Type: EB [FIGURE 1] The normals show a relative large scattering around the mean light-curve. This is caused by: 1. the small amplitude of the overexposed star and 2. the vicinity to the edge of the plates. HBV 477 will be further observed at Hamburg Observatory with the 60 cm photoelectric telescope in U, B and V. Orbital elements will be calculated later on. The photoelectric observations were partly carried out at Stephanion, Greece, where a 38 cm photoelectric telescope was placed by a NATO-grant. Hamburger Sternwarte Germany H. BOSSEN