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[vsnet-obs 799] more about DH Aql

  More information of historical outbursts of DH Aql:

   After discovery as a variable star, DH Aql was confirmed to be a
large-amplitude dwarf nova by Tsessevich (1969).  He observed three
outbursts from 268 Sternberg plates.  These outbursts were all short-
lived (lasting less than a few days), accompanied by a rapid decline
up to 1.3 mag day$^{-1}$.  He deduced from these observations the otburst
cycle length of DH Aql as 268 days.  The General Catalogue of Variable
Stars (GCVS) adopted these outburst parameters and UGSS-type classification.
A similar conclusion was obtained by more recent visual monitoring.
Vanmunster (1995) lists only three confirmed outbursts for the period
1991 -- 1994.  All the above facts -- 1) a large outburst amplitude,
2) existence of short outbursts with a rapid decline, 3) low outburst
frequency -- seem to suggest SU UMa-type classification rather than
SS Cyg-type suggested in GCVS, despite the fact that long outburst
suggesting superoutbursts seem to be missing at least from available
literatures.

   The Ouda team (Kyoto University) finally discovered superhump during
the 1994 September outburst.  The complete results will be soon available
as a preprint (Nogami et al. 1995).

   By the way, does anyone know a more complete bibliography of this star?
or, know any records of long outbursts?  We will appreciate and will
certainly acknowlege any information.

References:

Tsessevich V. P. 1969, Astron. Tsirk. No. 529
Vanmunster T. 1995, ``Outburst Activity Data on Selected Cataclysmic
   Variables"


Regards,
Taichi Kato