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THE ASTRONOMER Electronic Circular No 1513      2000 Apr 13 20.17UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK             GMH at AST.STAR.RL.AC.UK
WORLD WIDE WEB                    http://www.demon.co.uk/astronomer
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BG GEM

Gavin Ramsay (UCL) has asked if observers would monitor the above
RV star. He writes: "This is a star that has recently come to my 
attention (Benson et al, 2000 AJ, 119, 890). It has been classed as
an RV star but Benson suggests that it may be the first eclipsing 
black hole binary system. For follow-up work the problem is that the
ephemeris is not precise enough to get telescope time to cover the 
start and end of the eclipse. (The binary period is 91 days)."

BG Gem is at 06 03 30.8 +27 41 51 (2000) and there is a finding chart
at http://www.mssl.ucl.ac.uk/~gtbr/bggem_find.gif. The chart is
5 arcmin square and BG Gem is the brighter of the two stars in the
centre. The comparison stars on this chart are:

    R    B

A) 15.3 16.4
B) 15.2 16.4
C) 13.9 15.3
D) 11.7 13.5
E) 15.3 16.0
F) 14.1 15.0

Visual or CCD (preferably with blue filter) observations would be very
welcome during this month.

Please send any observations to the undersigned and I will forward them
to Gavin.

Nick James (ndj@astro1.demon.co.uk).