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			AAVSO ALERT NOTICE 183 (April 5, 1994)

1325+47 SUPERNOVA 1994I IN NGC 5194

We have been informed through the Central Bureau for Astronomical Telegrams (IAU Circulars 
5961, 5962) and the Nova Network of the discovery of a supernova 14.2" east and 12.3 " south of 
the nucleus of NGC 5194 (M51, the Whirlpool Galaxy), which is located at

R. A. = 13h 27m 47.625	Decl. = +47deg 26' 59.1"(1950).

First announcement of the supernova came from Tim Puckett and Jerry Armstrong, Atlanta, GA, 
on Apr 2.17 UT at 13.5 (CCD discovery). Other independent discoveries include Wayne Johnson 
and Doug Millar, Anza, CA, (visual discovery and CCD confirmation) on Apr 2.19 UT at V 
magnitude 13.7; Richard Berry, Cedar Grove, WI, on Apr 2.21 (no magnitude, CCD); Y. Fujita, 
Kuma-Kogen Observatory, Ehime, Japan, on Apr 2.62 at 14: (CCD); Reiki Kushida, Yatsugatake 
South Base Observatory, Japan, on Apr 2.66 at 13.8 (visual); and Terry Platt, Reading, England, 
on Apr 2.989 at 13.7 (CCD unfiltered).

The supernova was confirmed by B. Skiff, Lowell Observatory, on Apr 2.375 UT at visual 
magnitude 14.3; and by M. W. Richmond, Princeton University, and A. V. Filippenko, University 
of California at Berkeley (UCB), who with R. R. Treffers and S. D. Van Dyk (UCB) obtained 
BVRI CCD images on Apr 2.5 UT with the 0.5-m Berkeley Automatic Imaging Telescope (BAIT) 
and the Leuschner Observatory Supernova Search reflector at Leuschner Observatory. They found 
the object to be very blue, at V = 14.00 on Apr 2.5 UT and V = 13.54 on Apr 3.4. 
Moderate-dispersion spectra obtained on Apr 2 UT by L. Armus and J. M. Mazzarella, Caltech, 
with the 5-m Hale reflector at Palomar Observatory showed broad undulations superposed on a 
generally featureless continuum (Nova Network, IAU Circular 5961). Additional visual, CCD, and 
spectroscopic confirming observations have come from many sources.

B. Schmidt and R. Kirshner, Harvard-Smithsonian Center for Astrophysics, reported that unreduced 
spectra taken independently by J. Peters and G. Bernstein on Apr 3.37-3.52UT suggested that this 
supernova was a Type II in its earliest phases (IAU Circular 5962). However, Filippenko, T. 
Matheson, and A. J. Barth (UCB) report that CCD spectra taken at Lick Observatory on Apr 4.4 
UT suggest that the supernova, which is strongly reddened, may instead be a Type Ib, although the 
Type II classification has not yet been ruled out. According to Richmond and Filippenko, the 
supernova, which was not visible down to R - 16.2 on images taken at Leuschner Observatory on 
March 28, may brighten to visual magnitude 11 (Nova Network).

Visual observations of SN 19941 submitted to the AAVSO and received via The Astronomer E826 
and Nova Network include: M. Mobberley, Cockfield, England, Apr 2.887 UT, 13.3 (+ Kodak 
2415); G. Hurst, Basingstoke, England, Apr 2.923,13.6; S. Coe, Phoenix, AZ, Apr 2 UT, 13.5 (no 
time given); T. Polakis, Phoenix, AZ, Sh UT, < 13.5(no date given); T. Hager, New Milford, CT, 
Apr 5.07,13.0; C. Scovil, Stamford, CT, Apr 5.11,13.0; R: Raphael, S. W. Harbor, ME, Apr 5.13, 
13.4:; R. Royer, Lakewood, CA, Apr 5 .23,13.6:; Scovil, Apr 5 .29,12.5 .

The supernova is just on the edge of the nucleus of the galaxy. Care needs to be taken with CCD 
images in subtracting the background so that the supernova does not appear artificially brighter 
than its comparison stars (Richmond, Nova Network).

Accompanying is a chart of NGC 5194 from the Thompson/Bryan Supernova Search Charts. The 
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 supernova, and report 
your observations to AAVSO Headquarters so that we may inform the astronomical community. 
Be sure to include the comparison star(s) you used in making your observation(s).

Congratulations to the discoverers!


T. Kato, Kyoto University, Japan, and the Central Bureau for Astronomical Telegrams (IAU 
Circular 5961) report that on March 28, T. Hirayama, National Astronomical Observatory, Tokyo, 
Japan, reported the photographic discovery of an object by M. Wakuda, Ryuyu, Shizuoka, Japan, 
on Mar 14.825 UT at about magnitude 10.7 (T-Max 400 film, green filter). Wakuda reported no 
image brighter than 12.5 through 1992. The position of this object is

	R. A. = 18h Slm 43s	Decl. = -19deg 45' 54" (1950, uncertainty 10").

According to T. Kato, photographs by M. Yamamoto, Okazaki, Aichi, Japan, show the object's 
apparent variability of 10.5-11.5 (POO filter) since Mar 29, 1993, with no earlier detection. 
Yamamoto's observations (reported via K. Hirosawa and T. Kato) include: 1993 Mar 30 (Japan 
Standard Time), 11.5; May 23, 11.5; Jul 15, 11.0; Nov 3, 10.7; 1994 Feb 13, 11.0; Mar 11, 10.5.

Other observations of this object include: photometry by A. C. Gilmore, Mt. John Observatory, 
New Zealand, Mar 30.72 UT, preliminary V = 10.61; visual observations: G. Poyner, Birmingham, 
England, Mar 29.83,11.4; Apr 2.86,11.5 (77Ce Astronomer E82); C. Scovil, Stamford, CT, Apr 5.29, 

Evaluation of spectroscopic observations made by E. K. Grebel, European Southern Observatory, 
and H. W. Duerbeck, Astronomical Institute, Munster, suggest that this object is a symbiotic nova 
in a slightly progressed state (IA U Circular 5961).

C. Scovil, Stamford, CT, reports that he could not see a corresponding image on plates taken at 
Stamford Observatory in 1977 and 1980.

Please use the enclosed AAVSO chart by C. Scovil to observe this object, and report your 
observations to AAVSO Headquarters. Be sure to include the comparison star(s) you used.

Please use the charge-free telephone number (800-642-3883) or our regular telephone number to 
call in your observations. The answering machine at AAVSO Headquarters is on nights and 
weekends for your convenience.


Observers are reminded that all observations telephoned in to AAVSO Headquarters during a 
month need to be submitted to the AAVSO as a monthly report as soon after the beginning of the 
next month as possible. Without this monthly report, the observations you telephone/email/fax 
in on a nightly basis cannot be added to the AAVSO International Database for their long-term 
use by the astronomical community. If you do not presently submit monthly reports to the AAVSO 
or if you have questions about submitting monthly reports, please contact Headquarters.

Thank you very much for your observing efforts and your valuable astronomical contributions.

Good observing,

Janet A. Mattei 

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