|#1. Astrotel Observatory, Karachay-Cherkessia, Russia;
#2. Surgut, Russia;
#3. Ka-Dar Scientific Center and Public Observatory, Moscow, Russia
Received: 7.10.2009; accepted: 5.11.2009
(E-mail for contact: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org)
1. Three primary minima: HJD(TT) 2455038.3813, 2455039.3198, 2455100.2980. Min II = 15.89.
2. Three maxima: HJD(TT) 2455031.4094, 2455039.4523, 2455100.3348.
3. Three primary minima: HJD(TT) 2455034.4318, 2455039.4109, 2455100.2374. Min II = 17.01.
4. Primary minimum: HJD(TT) 2455032.3487. Min II = 13.15.
5. A close pair of stars 2MASS 23021634+4207262 and 2MASS 23021595+4207210. The angular resolution of our telescope is insufficient to determine which of the two stars varies. The coordinates in the table are for the blend of the two stars from the USNO-A2.0 catalogue (Monet et al. 1998). We observed two primary minima: HJD(TT) 2455032.4582, 2455039.4412. Min II = 12.05.
6. Primary minimum: HJD(TT) 2455024.3986.
7. A close pair of stars USNO-A2.0 1275-18118840 and USNO-A2.0 1275-18118785. The angular resolution of our telescope is insufficient to determine which of the two stars varies. Infrared colors J-H = 0.676, H-K = 0.086 and J-K = 0.762 (2MASS) of USNO-A2.0 1275-18118840 are consistent with a K spectral type star (Bessell and Brett 1988). Infrared colors J-H = 0.262, H-K = 0.184, J-K = 0.446 (2MASS) of USNO-A2.0 1275-18118785 are consistent with an F spectral type star (Bessell and Brett 1988) and RRAB classification. Four maxima: HJD(TT) 2455024.3694, 2455032.3054, 2455037.4399, 2455039.3162.
During observations of the field of omicron Andromedae we discovered seven new variable stars. Our observations were carried out at Astrotel-Caucasus observatory using 80-mm f/6 ED refractor, equipped with an unfiltered SBIG ST-2000XM CCD camera. In total, 689 images with 5-minute exposures were obtained on JD 2455024 - 2455100. For basic reduction for dark current, flat fields and bias, we used IRAF routines. For search and photometry of new variable stars we applied VaST software by Sokolovsky and Lebedev (2005). The comparison star is GSC 3224-01667 = USNO-B1.0 1327-0605901 (23:00:20.07, +42:44:45.9, J2000; R1 = 13.17, R2 = 13.28). Unfiltered magnitudes were calibrated using the comparison star, assuming Rcomp = 13.225. Coordinates of the variable stars in the table were drawn from the 2MASS catalogue (Cutri et al. 2003) if another source is not specified in the Comments. For search for periods and epochs of primary minima and maxima we use Peranso software (www.peranso.com).
Bessell, M.S., Brett, J.M., 1988, PASP, 100, 1134
Cutri, R.M., Skrutskie, M.F., van Dyk, S., et al., 2003, 2MASS All Sky Catalog of Point Sources, Centre de Donnees Astronomiques de Strasbourg, II/246
Monet, D., Bird, A., Canzian, B., et al., 1998, USNO-A2.0, A Catalog of Astrometric Standards (U.S. Naval Observatory, Washington, DC), Centre de Donnees Astronomiques de Strasbourg, I/252
Sokolovsky, K., Lebedev, A., 2005, in 12th Young Scientists' Conference on Astronomy and Space Physics, Kyiv, Ukraine, April 19-23, 2005, eds.: Simon, A.; Golovin, A., p.79