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THE ASTRONOMER Electronic Circular No 2359      2007 Jly 25 19.03UT
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      Backup: gmh@wdcc1.bnsc.rl.ac.uk
WORLD WIDE WEB                         http://www.theastronomer.org
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NOVA MESSIER 31 2007 12
The nova reported on E-Circular 2357 and first announced on The 
Astronomer's Telegram 1146 has also been referred to in the note below 
as M31N 2007-7c.

W. Pietsch, Max Plank Institut has reported on ATEL 1149 that the 
optical nova was detected on 2007 July 19.00741 in the R band when its 
brightness was still rising. During the Swift XRT and UVOT observations 
of nova M31N 2006-11a performed from 2007 July 12 to 18 the new nova was 
also in the field of view. While during UVOT observations with the UVW2 
filter on 2007 July 12 no source was visible at the position of the new 
nova (limit of 19.6), the nova was detected with a significance of more 
than 20 sigma in two Swift UVOT UVW2 images (1600 s and 1200 s exposure) 
centred on 2007 July 18.888 and 18.953. Its brightness was 17.68.

A. Rau, California Institute of Technology, et. al., report on ATEL 1153 
that on 2007 July  21.46 UT a spectrum of the nova candidate was 
obtained with Double-Beam Spectrograph on the  Palomar Hale-5m 
telescope.
The H-alpha  line  displays a  P-Cygni  profile.   The measured
expansion   velocity is -1630+/-20 km/sec  (blue shifted), based on
measurements of the Ca H+K lines, the G Band, H-beta, Mg lines and the 
near-infrared Ca-triplet. Taking into account the average radial 
velocity of M31 of about  -300 km/sec,  the  actual expansion velocity 
for the nova is estimated to be approximately 1330 km/sec.

Further CCD imaging at the 1.3m Ritchey Chretien f/7.5 telescope at
Skinakas Observatory, Crete, Greece showed the nova at a brightness of 
R=16.4, 15.8, 16.0, 17.1 on 2007 July 20.0078, 21.0425, 22.0720, 24.0462 
UT respectively. The photometric evolution shows that the nova reached 
its maximum brightness in R around 2007 July 21 at about the same time 
as the spectrum was taken. Novae like this, brighter than 16 mag in R 
stand out among the ~20 novae expected in the central area of Messier 
31.

HT CAM
Patrick Schmeer, Germany, reports a visual estimate of 12.6 on July 
24.018UT for HT Cam using a 0.203-m Schmidt Cassegrain and with 
reference to a sequence by Henden and Sumner.
Akira Arai, Makoto Uemura Hiroshima Univ. Japan report confirmation of 
the current outburst using the 1.5-m KANATA telescope. HT Cam was to be 
4-5mag brighter than its quiescence (about 18mag).

HT Cam is currently 13.5 mag. This is fainter than the value reported by 
P.Schmeer ( V = 12.6 mag ). The decline phase has already begun. 
Observation: 20070724.76097 13.54V

Guy M Hurst