BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.152 1997, September 10 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: tvanmuns@innet.be TEL. 32-11-831504 CVC Web Page : http://www.astro.columbia.edu/~cba/cvc =================================================================== USNO 1425.09823278 [CV:, 13.3R - 19.9R] ======================================= Tonny Vanmunster, CBA Belgium Observatory reports a rebrightening of this newly discovered variable. Compared with observations of yesterday evening, the brightness increased by nearly 1.3 mag. The object currently is around (unfiltered) mag 15.2, but visually very likely is about 0.5 mag brighter. Our observations were made with a CCD camera, attached to a 0.25-m f/6.3 SCT (unfiltered). Here are some recent estimates : 1997 Sep 05.977 UT, 14.2 (T. Vanmunster, unfilt. CCD); Sep 06.810 UT, 13.9 (J. Pietz); Sep 06.831 UT, 14.45 (L. T. Jensen, unfilt. CCD); Sep 06.890 UT, 14.0 (J. Pietz); Sep 06.964 UT, 14.5 (T. Vanmunster, unfilt. CCD); Sep 06.980 UT, 14.0 (J. Pietz); Sep 07.810 UT, 15.5 (L. T. Jensen, unfilt. CCD); Sep 07.837 UT, 15.3 (T. Kinnunen); Sep 07.869 UT, 15.4: (G. Poyner); Sep 07.926 UT, 15.5: (G. Poyner); Sep 07.938 UT, 15.7 (T. Kinnunen); Sep 09.007 UT, [14.7 (G. Poyner); Sep 09.772 UT, [14.7 (T. Kinnunen); Sep 09.890 UT, 16.5 (T. Vanmunster, unfilt. CCD); Sep 09.974 UT, [14.7 (G. Poyner); Sep 10.819 UT, 15.2 (T. Vanmunster, unfilt. CCD); It's a pitty that this object is not followed more intensively by CCD observers worldwide. The present rebrightening clearly proves it should be a priority object for all dwarf novae photometrists ! V1251 CYG [UGSU, 12.5p - <15p] ============================== The superhumps in this object, announced in CVC 151, are now fully grown, as indicated by unfiltered CCD observations obtained at CBA Belgium Observatory during the nights of Sep 8/9, 1997 (3.2h run) and Sep 9/10, 1997 (4.7h run). The mean semi-amplitude on both nights was 0.25 mag, and the combined superhump period (derived using the PDM method) 0.075 +/- 0.001 d. Tonny Vanmunster