THE ASTRONOMER Electronic Circular No 501       1991 Mar 28 20.32UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP, England. Telephone:  (0256)471074 Int:+44256471074
Telex: 9312111261 Answerback: TA G                     JANET BOXES:
GMH at UK.AC.CAM.ASTRONOMY.STARLINK or GUYH at UK.AC.SUSSEX.CLUSTER
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NOVA HERCULIS 1991
Denis Buczynski, Conder Brow Observatory, reports a semi-precise
position measured from the second confirmatory photograph taken on
1991 Mar 25.208UT (1 minute exposure, T-Max 400 film, 5" Zeiss
Astrograph):
RA 18h44m12.01s DEC +12 10'44.3"(1950).
7 AGK3 star reduction.
The position is slightly uncertain due to heavy fogging of the
film resulting from the dawn sky. It does, however, agree
reasonably well with the result by Rob McNaught published on E500.
It also suggests that star 1 (cf E500) listed by McNaught, could
well be the pre-nova candidate.
We have subsequently heard that Richard West, European Southern
Observatory, has also proposed star 1 and provides a measure of
this star from glass copies of the Palomar Sky Survey:
RA 18h44m11.98s DEC +12 10'43.5"(1950).
He reports that the blue and red magnitudes are about 19 and
17.5 respectively.
A further measurement of star 1 has been reported by R.M.Humpreys
et al of the University of Minnesota:
RA 18h44m11.90s DEC +12 10'45.1"(1950).
They report magnitudes for blue and red of 20.6 and 18.25.
News of the discovery were passed to numerous professional
astronomers around the world by Denis Buczynski and the Editor
within hours of the first observation. J.Aycock et al, using the
UK Infrared Telescope on Mauna Kea (report relayed by Alan
Pickup, Edinburgh) obtained the following magnitudes:
Mar 26.67UT: J=6.11 +/-0.07; H=6.08 +/-0.04; K=5.46 +/-0.08.
Infrared spectra were also obtained with the 2.3-m telescope
at Siding Spring following relay of E499 by Rob McNaught to
T.E.Harrison. Fuller details will appear in 'The Astronomer'
in due course.
Mark Kidger relays that Carlos Martinez obtained an infrared
spectrum with the Carlos Sanchez Telescope and Kidger's
preliminary reductions are:
Mar 26.1397 J=5.45, H=5.06, K=4.55
    26.2679 J=5.41, H=5.08, K=4.62
(J is 1.26 microns, H=1.65 and K=2.20)
Mark comments that the nova seems to be quite highly reddened
and thus distant. He also mentions that the rate of decline is
quite exceptional, perhaps similar to V1500 Cygni (=Nova Cygni
1975).
Further visual estimates:
1991 Mar 25.80UT, 6.8 (McNaught, corrected from E500);
26.02UT, 7.3 (B.Granslo, Norway); 26.15, 7.2 (Russell Eberst,
Scotland); 26.16, 7.2 (Daniel Verde, Gran Canaria); 26.37, 7.5
(John Bortle, USA); 26.404, 7.7 (Bortle); 26.81, 7.6 (McNaught);
27.09, 7.7 (Daniel Fischer, Koenigswinter, Germany); 27.18, 8.1
(George Alcock, co-discoverer); 27.36, 7.8 (A.Hale, USA); 27.79,
8.1 (McNaught); 28.10, 7.9 (Gary Poyner, Birmingham); 28.20, 8.5
(Bill Worraker, Didcot),

Guy M Hurst