BELGIAN ASTRONOMICAL SOCIETY V.V.S. - Working Group Variable Stars Cataclysmic Variables Circular No.134 1997, April 14 Ed.: T. Vanmunster, Walhostraat 1A, 3401 Landen, BELGIUM Internet: tvanmuns@innet.be TEL. 32-11-831504 CBA Belgium Web Page : http://www.astro.columbia.edu/~cba/be =================================================================== DV UMa [UGSU, 15.4v - 20.6v] ============================ In a recent VSNET message, Tonny Vanmunster, CBA Belgium Observatory announced the discovery of superhumps in this system, hence classifying it as a UGSU type dwarf nova : "I performed unfiltered time series photometry on DV UMa at CBA Belgium Observatory last night (April 9/10, 1997), during 4.8 hours. The resulting light curve shows three eclipses and very prominent superhumps. These observations thus establish DV UMa as a new member of the UGSU-type dwarf novae." Joe Patterson, CBA (Columbia University), NY communicates following precise data on the superhump period : "I received a lot of data on DV UMa, coming from CBA Denmark (Lasse Jensen), CBA West (Dave Harvey) and CBA Belgium (Tonny Vanmunster), and the star now shows very large superhumps at nu = 11.22 +- 0.05 c/d. The superhump amplitude is about 0.35 mag. One very large run on JD 548 has an obvious signal at 23.52 c/d, which I take to be the first harmonic of nu-orb, a la AL Com and WZ Sge." In CVC 133, we listed a mid-eclipse ephemeris for DV UMa, published by Taichi Kato, consisting of two possible alternatives. An analysis by T. Vanmunster of a set of DV UMa time series photometry data, obtained on April 9/10 at the Center for Backyard Astrophysics of Dave Skillman (CBA East) and CBA Belgium, clearly indicates that the best fit ephemeris is the first one : Min.HJD = 2446854.7487 + 0.085852614 E (1), The observed eclipses fit within the 0.002 day error mentioned by Taichi Kato [CVC 133]. V795 Cyg [UGSS, 13.4p - <17.9:p] ================================ The outburst of V795 Cyg, mentioned in CVC 132, has received some further coverage. As to the dwarf nova subtype status of V795 Cyg, we still have to conclude that this object most likely is of an SS Cyg subtype. We performed time-series CCD photometry on V795 Cyg at CBA Belgium Observatory on three successive nights (Apr 7/8, Apr 8/9 and Apr 9/10) for a total of 7.1 hours, but on each occasion the light curve failed to reveal superhumps. Tonny Vanmunster