BELGIAN ASTRONOMICAL SOCIETY V.V.S. -  Working Group Variable Stars
Cataclysmic Variables Circular No.142                  1997, May 25
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
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DM Lyr [UGSU, 13.6p - 18p]
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Tonny Vanmunster, CBA Belgium reports his visual detection of an
outburst of this object, which is part of the Recurrent Objects 
Programme of The Astronomer/BAAVSS. Gary Poyner, UK has been
able to confirm the outburst. The observations are :

1997 May 24.972 UT, <14.9  (G. Poyner, 0.40-m refl., seq: VSNET);
     May 25.216 UT, <14.8  (G. Hanson, 0.46-m refl., seq: AAVSO);
     May 25.913 UT,  15.1  (T. Vanmunster, 0.35-m refl., seq: AAVSO);
     May 25.933 UT,  14.9: (G. Poyner);
     May 25.954 UT,  15.0: (G. Poyner);
     May 25.961 UT,  15.2  (T. Vanmunster, 0.25-m SCT, unfilt. CCD);

DM Lyr was last seen in outburst on July 7, 1996 [CVC 98]. It
became as bright as mag. 13.7 [CVC 99], around July 11, 1997.

CCD photometry at Kyoto University, Japan (Kato) and CBA Belgium
(Vanmunster) independently revealed the SU UMa-type nature of
this dwarf nova [CVC 101]. Both teams derived a superhump period
of 0.067d +/- 0.001d.


Tonny Vanmunster