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THE ASTRONOMER Electronic Circular No 2044      2004 Oct 01 14.06UT
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.theastronomer.org
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SUPERNOVA 2004et IN NGC 6946
S. Moretti has reported discovery of a magnitude 12.8 supernova in the 
galaxy NGC 6946 on CCD images of 2004 Sept 27 using a 0.4-m telescope at 
Ravenna. The position is:
RA 20h 35m 25.33s DEC +60 07'17.7" (2000).

According to the announcement on IAUC 8413 a spectrum obtained on 
September 28 with the 1.82-m Asiago telescope shows a relatively
featureless spectrum with a very broad, low-contrast H_alpha emission.

Hitoshi Yamaoka, Japan informs us that K. Itagaki, Japan found nothing 
at the location of SN 2004et on an unfiltered CCD image taken on Sept. 
19.655 UT with a 0.60-m reflector to a limit of magnitude 18.5.

W. Li and A. V. Filippenko, University of California, Berkeley; and
S. D. Van Dyk, Infrared Processing and Analysis Center, California
Institute of Technology, report that SN 2004et was imaged on Sept. 30 UT 
with the 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick 
Observatory, yielding end figures RA 25.37s, DEC 17.8" (2000).

A faint object, possibly extended, appears at this location on 
multi-band images of NGC 6946 taken with the Kitt Peak 0.9-m telescope 
on 1989 May 30.  Based on calibrations of the field on three photometric 
nights with the Lick Nickel 1-m telescope, they measure the object at R 
= 20.8 +/- 0.2, adding that it was not detected in the Kitt Peak B- and 
I-band images (B > 21.3, I > 19.7).

Using a distance of 5.5 Mpc to NGC 6946 and E(B-V) = 0.41 mag, the 
absolute magnitudes of the object are M_B > -9.1, M_R = -8.9, and M_I > 
-9.7.

Hazel McGee, West Clandon, England, advises us that a visual observation 
was obtained using the AAVSO chart of 2004 Sept 30
2004 Sept. 30.851   12.6v.

A preliminary AAVSO chart and sequence can be found at:
http://www.aavso.org/cgi-bin/searchcharts3.pl?name=ngc%206946

Yamaoka adds his calculation of offsets as: 250"E and 120"S. He mentions 
that this galaxy is one of the most SN productive galaxies (SNe 1917A, 
1939C, 1948B, 1968D, 1969P, 1980K and 2002hh), with the current object 
being the eighth supernova in the same galaxy, a new record!

Guy M Hurst