THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
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AAVSO ALERT NOTICE 247 (April 29, 1998)
1224-22 SUPERNOVA 1998bn IN NGC 4462
We have been informed by the Central Bureau for Astronomical Telegrams (IAU
Circular 6886) that W.D. Li, M. Modjaz, R.R. Treffers, and A.V. Filippenko,
University of California at Berkeley, report the discovery of a supernova
made during the course of the Lick Observatory Supernova Search, using the
0.8-m Katzman Automatic Imaging Telescope. Unfiltered CCD images obtained
on April 17.3 UT and April 27.3 UT showed the supernova at magnitude
approximately 17.4 and 13.7, respectively. No star was seen at the position
of SN 1998bn on the Digital Sky Survey.
SN 1998bn is located at:
R.A. = 12h 29m 18.88s Decl. = -23 degrees 09' 49.2" (equinox 2000.0)
and is about 32.3" west and 9.7" north of the nucleus of NGC 4462.
Spectroscopic confirmation was obtained by F. Patat, European Southern
Observatory, and M. Maia, Observatorio Nacional, Rio de Janeiro (IAU Circular
6888), using the ESO 1.5-m telescope (+ Boller & Chivens spectrograph). They
report that full reduction of their CCD spectrogram taken on April 28.10 UT
indicates that SN 1998bn is a Type Ia supernova about 4 days before maximum,
very similar to SN 1994D.
Observations of SN 1998bn submitted to the AAVSO include: Apr. 28.6611 UT,
13.9, R. Stubbings, Drouin, Victoria, Australia (vsnet sequence); 28.714,
13.4:, B. Monard, Pretoria, S. Africa (EX Hya sequence); 28.749, 13.5:, Monard
(Monard sequence); 28.795, 13.5:, Monard (Monard sequence).
Accompanying is an AAVSO 'e' scale Supernova Search Preliminary chart of
NGC 4462, prepared by C. Scovil and showing the location of SN 1998bn.
Please use this chart to observe the supernova, and report your observations
of 1224-22 SN 1998bn to AAVSO Headquarters, making sure you indicate which
comparison stars you used.
Congratulations to the Lick Observatory Supernova Search team on their
CHARTS AVAILABLE ON AAVSO FTP SITE
Chart links obsolete, 11/2013: Create charts using VSP at http://www.aavso.org/vsp 
Electronic copies of the AAVSO chart of SN 1998bn in NGC 4462 mentioned in
this Alert Notice are available from our FTP site:
ftp.aavso.org (184.108.40.206), in /pub/alerts/alert247/
ftp.aavso.org (220.127.116.11), in /pub/charts/crv/sn1998bn/
The chart may also be accessed through our Web site at the following address:
The answering machine at AAVSO Headquarters is on nights and weekends for your
convenience. Please call our charge-free number (800-642-3883) to report your
observations. We also encourage observers to send observations by fax to
617-354-0665 or by e-mail through the Internet to firstname.lastname@example.org .
Many thanks for your valuable astronomical contributions and your efforts.
Elizabeth O. Waagen, Senior Technical Assistant
on behalf of
Janet A. Mattei, Director
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