COMMISSION 27 OF THE I. A. U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                              Number 2488

                                                     Konkoly Observatory
                                                     Budapest
                                                     7 March 1984

                                                     HU ISSN 0374-0676





            IMPROVED POSITIONS FOR 15 CATACLYSMIC VARIABLE STARS


  Modern astronomical observations generally require accurate celestial
coordinates for source acquisitions and candidate confirmations among various 
observational wavelengths. Nevertheless, many important members of various 
classes of faint objects are still identified (or misidentified) through
the use of relatively poor coordinates that may be perpetuated for decades
in the literature. This paper presents new source positions, with accuracies
of order 1 arc-sec, for 15 cataclysmic variables.
  The star positions were measured with the Computer Assisted Astrometry
System of NRAO's Very Large Array. The system allows one to measure the position
of objects on the Palomar Observatory Sky Survey (POSS) prints by utilizing 
the Smithsonian Astrophysical Observatory Star Catalog as a source of
reference stars. The source names, types, and their measured 1950.0 coordinates
are presented in Table I in order of increasing right ascension, alpha.
The uncertainties in right ascension, Delta alpha, and declination, Delta delta, 
are determined
from the variances of the residuals of the fitted reference stars (typically
eight stars were fitted). These uncertainties include an empirically determined
0.3 arc-sec measuring precision of the source itself.
    It is hoped that these position will serve to correct published errors
of several minutes of  arc for some sources and to confirm the more accurately
reported positions. The author wishes to thank Dr. Derek Wills who earlier
provided the position for SU UMa. This position is included here because its
accuracy is comparable or even superior to the other measurements since it
was measured with the superb plate measuring engine of the McDonald Observatory
using techniques similar to those above with the POSS plates.





               TABLE I. POSITIONS OF CATACLYSMIC VARIABLES



SYSTEM       TYPE^+      RIGHT ASCENSION  Delta alpha Delta alpha DECLINATION    deltadelta
                            alpha                                    delta       (arc-sec)
                           (1950.0)          (time)     (arc-sec)  (1950.0)
                                        
KT Per       DN        01h34m01.s67          0.05s       1.2    +50d42' 01.7"      1.4
                                                                                        
RX And        DN        01 01 46.01           0.05        1.0     41 01 52.2        1.1 

RW Tri        NL        02 22 41.57           0.06        1.0     27 52 20.3        0.6
                                        
CN Ori        DN        05 49 40.47           0.06        1.0    -05 25 41.0        0.8

SS Aur        DN        06 09 35.57           0.04        0.8    +47 45 13.8        0.4
           
IR Gem        DN        06 44 25.75           0.04        0.7    +28 09 42.8        0.9
                                                                                        
U  Gem        DN        07 52 07.78           0.03        0.5    +22 08 02.4        0.6

YZ Cnc        DN        08 07 52.71           0.06        1.0    +28 17 31.0        1.2
                                                                                       
SU UMa        DN        08 08 05.45           0.02        0.7    +62 45 22.8        0.4
                                                               
Z  Cam        DN        08 19 39.64           0.01        0.5    +73 16 24.7        1.1
                                                                                      
UX UMa        NL        13 34 42.06           0.05        1.2    +52 10 04.4        1.1
                                       
V603 Aql      N         18 46 21.42           0.06        0,9    +00 31 34.8        0.8 
                                                    
EM Cyg        DN        19 36 42.13           0.07        1.2    +30 23 33.5        0.6
                                                                
SS Cyg        DN        21 40 44.42           0.03        0.6    +43 21 21.4        0.6
                                                             
RU Peg        DN        22 11 35.50           0.06        1.0    +12 27 16.8        0.7
                                                    


  
  +^ DN, dwarf nova; NL, nova-like; N, old nova.





                             ALAN L. KIPLINGER

                  Laboratory for Astronomy and Solar Physics
            Goddard Space Flight Center and Applied Research Corporation
                                 Landover, Maryland
                                     U.S.A