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                AAVSO ALERT NOTICE 249 (May 11, 1998)

1041+12 SUPERNOVA 1998bu IN NGC 3368 (= M96)

We have been informed by Mirko Villi, Forli, Italy, and by the Central Bureau
for Astronomical Telegrams (IAU Circular 6899) of Villi's discovery of an
apparent supernova in NGC 3368 (= M96).  Unfiltered CCD images taken May 9.9 UT
by Villi show the object at about magnitude 13 and located about 60" north of
the nucleus of the galaxy.  No object was visible at the location of the object
on a CCD image taken by Villi on April 21.9, nor was anything visible on images
in several atlases.

Information provided by M. Aoki, Toyama, Japan, from a CCD image he obtained
with a 0.43-m reflector in bad weather conditions on May 10.618 UT, and
reported by S. Nakano, Sumoto, Japan, shows SN 1998bu at V magnitude 11.8 and
located at:

     R.A. = 10h 46m 46.03s  Decl. = +11 degrees 50' 07.1"  (equinox 2000.0)

and 4.3" east and 55.3" north of the center of NGC 3368.  Previous frames taken
by Aoki do not show an object at this position.

Visual confirmation has also been reported by the following (IAU Circular 6899):
     Brian A. Skiff, Lowell Observatory, Flagstaff, AZ, observed the object
in full moonlight at visual magnitude approximately 12.0-12.5 on May 10.33 UT,
using the Lowell 53-cm telescope;
     Dalibor Hanzl, Brno, Czech Republic, obtained a CCD image showing the
object at V magnitude 12.37 on May 10.835 UT, using a 0.40-m reflector + CCD.

Accompanying is a chart of NGC 3368 from the Thompson/Bryan Supernova Search
Charts.  The apparent supernova is not marked on the chart due to its proximity
to the galaxy nucleus, but observers should not have difficulty locating it.
Please use this chart to observe the apparent supernova, and report your
observations of 1041+12 SN 1998bu to AAVSO Headquarters, making sure you
indicate which comparison stars you used.

Congratulations to Mirko Villi on his most recent discovery!


The AAVSO's charge-free (800) number will be changing.  Effective June 1, 1998,
this number will be
which is the same as

This number may be used from telephones in the United States and Canada to
report observations at no cost to the observer.


Electronic copies of the AAVSO chart of apparent SN 1998bu in NGC 3368
mentioned in this Alert Notice are available from our FTP site:
 (, in /pub/alerts/alert249/
or (, in /pub/charts/leo/sn1998bu/

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 through May 31,
888-802-STAR as of June 1) 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

Many thanks for your valuable astronomical contributions and your efforts.

Good observing!

Janet A. Mattei

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484