COMMISSIONS 27 AND 42 OF THE IAU 
         INFORMATION BULLETIN ON VARIABLE STARS 
                   Number 3706
 
                                  Konkoly Observatory 
                                  Budapest 
                                  2 April 1992 
 
                                  HU ISSN 0374 - 0676 
 
 
       CV IN CORVUS: NO OUTBURSTS ON BAMBERG PLATES 
 
  
   The discovery by C.W. Tombaugh of a cataclysmic variable in 
Corvus at alpha = 12h17m49s and delta = -18d10'27" (1950.0) was 
communicated by Levy (1990). The search by Levy through 260 
Harvard College Observatory plates revealed 9 another maxima 
between 1932 and 1988. Another outburst was reported in 1990 
(Levy, 1990) increasing the number of known outbursts to 11. The 
magnitudes of these outbursts were estimated to reach up to 12m. 
   The position of the object was investigated on 107 plates 
taken with 7-25 cm aperture cameras at the Southern Stations of 
the Bamberg Observatory during years 1964-1967 and 1971-1974. The 
limiting magnitudes of these plates (13-15 mag.) are too low to 
enable the studies of the object in quiescence (approx 17-18 mag.) but 
is enough to record the outbursts of the object as described by 
Levy (1990). 
   The investigated Bamberg plates represent nearly 100 h of 
monitoring time. Assuming the typical dwarf nova behaviour, i.e. 
the duration of the outbursts > 1 day, one would expect to detect 
~ 4 brightenings (taken the 9 outbursts detected on 260 HCO 
plates into account). Since none was found, we conclude that 
there probably exists active and inactive long-term periods in 
which the outbursts occur and/or not occur. Similar behaviour 
was already observed e.g. in GK Per (Hudec, 1981). With the 
exception of the 1971 Apr 20 outburst, all other brightenings 
revealed by Levy (1990) appeared in the time periods 1932-1952 
and 1983-1990, while the majority of our data corresponds to time 
period 1964-1967 with only sparse data for 1971-1974. Thus 
I conclude that the outbursts were less frequent or even absent 
in the time period 1964-1967. Another explanation is however also 
possible, namely that the outbursts are, in fact, fainter than 
~ 14m, i.e. fainter than reported by Levy (1990). 
Acknowledgements 
 
I would like thank to Prof. I. Bues and to the staff of the Bamberg 
Observatory for making the plates available and for the support in 
this study. 

 
                                                 R. HUDEC 
                                                 Astronomical Institute 
                                                 251 65 Ondrejov 
                                                 Czechoslovakia 
 
References: 
 
Hudec, R.: 1981, Bull. Astr. Inst. Czechosl. 32, 93.  [BIBCODE 1981BAICz..32...93H ]
Levy, D.H.: 1990, I.A.U. Circ. No. 4983. [BIBCODE 1990IAUC.4983....1L ]