COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                       Number 2303

                                       Konkoly Observatory
                                       Budapest
                                       28 March 1983

                                       HU ISSN 0374-0676


           A PHOTOELECTRIC SECONDARY MINIMUM OF AR Lac



  The first observations from the new Dark Sky Observatory at Appalachian
State University have yielded times of minima in two colors for a secondary
eclipse of AR Lacertae. The observations were made with the 46 cm telescope
and photoelectric photometer equipped with standard UBV filters and an uncooled
1P21 photomultiplier tube. The instrument, in fact, is the same as used by
Caton et al. (1977). The amplifier output voltage is converted to a frequency
and averaged by a Commodore 4016 microcomputer.

  The comparison star used was BD+47d3711, approximately three degrees away
and almost identical in color to AR Lac. Effects of differential extinction
were not removed, nor were the data converted to standard UBV. The reduced
data were analyzed using the method of Kwee and Van Woerden (1956), using a
computer program by Mallama (1982). The resulting times of minima for the
two colors are:


           Color    Hel. J.D.      Mean Error
           ----------------------------------
           visual   2444898.6828 + 0.0011
           blue            .6869 +  .0023
           ----------------------------------


 I am grateful to the University of Florida for the loan of their photometer.




                   D. B. CATON
             Department of Physics and Astronomy
             Appalachian State University
             Boone, North Carolina 28608
             U.S.A.


References:

Caton, D.B., Fallon, F.W. and Wilson, R.E., 1977, Publ. A.S.P. 89, 530 [BIBCODE 1977PASP...89..530C ]
Kwee, K.K. and Van Woerden, H., 1956, B.A.N. 12, 327 [BIBCODE 1956BAN....12..327K ]
Mallama, A.D., 1982, I.A.A.P. Comm. No. 7, 14 [BIBCODE 1982IAPPP...7...14M ]