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"Peremennye Zvezdy", Prilozhenie, vol. 8, N 10 (2008)

New UV-type Variable Star USNO-A2.0 0900-20386773

T. Kryachko^#1, A. Samokhvalov^#2, B. Satovskiy^#1

#1. Astrotel Observatory, Karachay-Cherkessia, Russia; #2. Surgut, Russia

ISSN 2221–0474

Received:   6.02.2008;   accepted:   28.02.2008
(E-mail for contact: bredfild@mail.ru, sav@surgut.ru, bs25@mail.ru)

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Star Name: USNO-A2.0 0900-20386773 Coordinates (J2000): 23 22 06.63, +06 35 16.5 Variability type: UV;   Limits, System: -1.14 to -0.05 (delta m, unfiltered);     Period: Epoch(max): JD

Remarks:

We present the discovery of a new UV-type star USNO-A2.0 0900-20386773, found by T. Kryachko on images obtained with automated, Internet-operated telescopes at Astrotel Caucasus Observatory. The field with the new variable was observed during 3 nights in November 2007 (49 images, a total of 4 hours of observations) with a SkyWatcher 80ED refractor (D = 80 mm, F = 480 mm) equipped with a SBIG ST-2000XM CCD camera without filters; and during 11 nights in November 2007 - January 2008 (316 images, 26.5 hours of observations) with a Takahashi FRC-300 telescope (D = 300 mm, F = 2350 mm) equipped with a SBIG STL-11000 CCD camera, without filters. Exposure time of a single frame was 300 sec in both observation sets. The MaxIm DL software was used to control CCD cameras, to correct the frames for bias, dark and flat field and to perform photometry. The comparison (USNO-A2.0 0900-20385124) and check (USNO-A2.0 0900-20384832) stars are marked on the finding chart. A single UV-type flare was detected at JD 2454457.13 (see the light curve). The observations are available electronically.