COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3268

                                                         Konkoly Observatory
                                                         Budapest
                                                         28 November 1988

                                                         HU ISSN 0374 - 0676


                      Variables Near NGC 6760

The work of Sawyer (1953) identified four variables near this globular cluster.
Minimum and maximum magnitudes were estimated, though no periods were 
determined. Sawyer Hogg (1973) lists the variables again, with reference to some
eclipsing variables in the field (V406, V407, and V1297 Aql ). The eclipsing
variables however do not lie as near to the cluster as the other four found by
Sawyer and should not be considered as possible members to NGC 6760.
Armandroff (1988) was able to determine that variable V1 is not an RR Lyrae
member of the cluster, though it might be a Mira belonging to the cluster. He
also provides the first color-magnitude diagram from CCD photometry for this
cluster.
   It should be noted that Armandroff (1988) has misidentified variable V4 
because it does not appear clearly on the chart given by Sawyer (1953). In her
chart, V4 really lies at the tip of the arrow drawn and is NOT the star seen a
small distance away from the arrow. This bulletin is meant to prevent future
misidentifications by providing an improved finding chart for the variables,
especially V4. Figure 1 is a 20 minute CCD frame of NGC 6760 taken on October
23, 1988 (UT) at Lick Observatory's 1-meter Nickel Telescope using a narrow
(100 A) bandpass I filter at 8000 A. North is up, east to the left, and the
scale is indicated. Many faint stars have been suppressed in this diagram.
The four variables identified by Sawyer are indicated. A CCD exposure in V is
given in Armandroff (1988) for NGC 6760.
   The identity of V4 was confirmed using Sawyer's positions and the Northern
Proper Motion Survey astrograph plates at Lick, on which V4 showed a change of
approximately 3 magnitudes. Together, V4's strong red color (through comparison
with a CCD V filter frame), large amplitude, and late-type spectrum obtained at the
Nickel telescope lead this author to suspect that V4 is a possible Mira
variable belonging to the cluster. V1, also a possible Mira, has a late-type
spectrum similar to V4's. No periods have ever been determined for these
variables however. Continued observations will be made with an effort at


                              [FIGURE 1]


determining the variables' periods and I would welcome receiving magnitude
estimates from fellow investigators with the aim of establishing the light
curves.


                     CHARLES F. PROSSER

                Board of Studies in Astronomy
                     and Astrophysics
                    Natural Sciences II
                Univ. of California Santa Cruz
               Santa Cruz, California 95064 USA



References:

Armandroff, T. 1988, Astron. J., 96, 588. [BIBCODE 1988AJ.....96..588A ]
Sawyer, H. 1953, J.R. Astron. Soc. Can., 47, 229. [BIBCODE 1953JRASC..47..229S ]
Sawyer Hogg, H. 1973, Publ. David Dunlap Obs., 3, No. 6. [BIBCODE 1973PDDO....3....6S ]