COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1748

                                 Konkoly Observatory
                                 Budapest
                                 1980 February 27


     ACCURATE POSITIONS OF SOME R CORONAE BOREALIS VARIABLE STARS


The absolute equatorial coordinates alpha and delta (1950.0) of a group of 14 R
Coronae Borealis variable stars were determined.

The identification of these stars appeared to be difficult due to their quite
irregular variations as well as by the fact that the positions given in the
General Catalogue of Variable Stars (Kukarkin et al. 1969) are only
approximate.

The average positions determined in this work (Table I) were obtained from, at
least, two plates of four square degrees each, taken with the Gauthier
Astrograph telescope. The x, y rectangular coordinates were measured using a
Wild A7 measuring machine with an accuracy of 5 microns whilst the reductions
to right ascension and declination were performed with an Olivetti P 6060
Computer applying the least square method. The accuracy of both coordinates is
+-0.1" (mean square deviation).

On each plate, 8 reference stars were taken using in all cases the Cape
Photographic Catalogue for 1950.0 with the exception of stars V 1860 Sgr, GU
Sgr, and MV Sgr, for which the Transactions of the Astronomical Observatory of
Yale University (1950.0) were used. The positions based on the Cape stars are
on the FK3 system for eq. 1950.0.

Table I

Star         alpha         (1950.0)       delta
UW Cen       12h 40m 26.400s  (26s)^*   -54d 15'14.55" (16")^*
 Y Mus       13  02  34.257   (34)      -65  14 43.74  (43)
DY Cen       13  22  27.136   (25)      -53  59 11.13  (11)
 Z Cir       13  47  03.135   (02)      -70  13 32.03  (23)
AE Cir       14  40  22.576   (23)      -69  10 57.69  (53)
 S Aps       15  04  21.448   (20)      -71  52 17.76  (01)
RT Nor       16  20  02.844   (04)      -59  13 46.60  (54)
RZ Nor       16  28  45.063   (40)      -53  10 47.63  (09'37")
WX CrA       18  05  25.704   (26)      -37  20 16.58  (08")
RS Tel       18  15  07.050   (07)      -46  34 07.64  (02)
V 1860 Sgr   18  18  24.069   (24)      -24  46 38.80  (34)
GU Sgr       18  21  11.761   (12)      -24  17 08.29  (16'46")
MV Sgr       18  41  33.090   (33)      -21  00 22.91  (24")
RY Sgr       19  13  16.927   (17)      -33  36 42.34  (40)

^* Coordinates from the General Catalogue of Variable Stars (Kukarkin et al.
1969) for 1950.0 are given in brackets.

Identification charts for these stars are available on request from the author.

I am indebted to Dr. L.A. Milone under whose direction this project was
conducted.


M.M. VILLADA
Observatorio Astronomico
Laprida 854
5000 Cordoba
Argentina

Reference:

Kukarkin, B.V., Kholopov, P.N., Efremov, Yu.N., Kukarkina, N.P., Kurochkin,
   N.E., Medvegeva, G.I., Perova, N.B., Fedorovich, V.P., and Frolov, M.S.,
   1969, General Catalogue of Variable Stars, Moscow State University
   [BIBCODE 1969gcvs.book.....K ]