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		THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 
				25 Birch Street, Cambridge, MA 02138 USA 
			BITNET: aavso@cfa8 SPAN: nssdca::cfa8::aavso
			Tel. 617-354-0484 FAX 617-354-0665

			AAVSO ALERT NOTICE 141 (April 17, 1991)

SUPERNOVA 1991T IN NGC4527

AAVSO member Stephen Knight (East Waterford, ME) visually discovered a supernova 
in the galaxy NGC 4527 on April 13.17 UT at approximately magnitude 14.0. The 
IAU Central Bureau for Astronomical Telegrams reports that the supernova was 
independently reported by Robert Evans (Hazelbrook, NSW, Australia), M. Villi 
and G. Cortini (Monte Colombo, Italy), and Wayne Johnson (Anza, CA). It was 
spectroscopically confirmed by astronomers at European Southern Observatory 
and Whipple Observatory, and is believed to be a type- I supernova discovered 
very close to or before maximum.

The supernova is offset 25.7" east and 44.14" north of the galaxy nucleus, and 
its precise position (1950.0, from R. McNaught, Anglo-Australian Observatory) is:

			RA 12h 31 m 36.91s	Dec. +02deg 56' 28.13"

Recent observations of the supernova include:

Apr.	4.48UT	<15			(Evans)
	9.9		<15		(Villi and Cortini)
	10		invisible	(near-infrared plate taken with Oschin Schmidt
						telescope, J. Mueller, Palomar Observatory, CA)
	13.17		14.0:		(Knight)
	14.14		13.6		(Knight)
	15.6		13		(Evans)
	15.9		13.0		(Villi and Cortini)
	16.26		13.5		(Johnson)
	16.35		12.9		(photometric V, G. Cutispoto, Catania Observatory, Italy)

The accompanying chart from Thompson and Bryan for NGC 4527 shows the position of 
the supernova. Please use the sequence on the accompanying Thompson and Bryan 
chart for NGC 4536, which is just to the north of NGC 4527, to estimate the 
supernova's brightness, and report your observations to AAVSO Headquarters.

Congratulations to Stephen Knight on his first supernova discovery, and to Bob 
Evans, M. Villi and G. Cortini. and Wayne Johnson for their independent discoveries!

NOVA HERCULIS 1991
This nova (see AAVSO Alen Notices 139 and 140) appears to have slowed down somewhat from its initial rapid decline. Recent observations include:

 
April	5.26 UT		10.7 S. Knight		10.33	12.2 J. McKenna
 	5.35		11.3 R. DeMartino	11.090	12.0 P. Schmeer
 	5.37		11.0 B. Bois		11.24	12.1 R. King
 	5.55		11.1 R. Royer		11.32	12.2 J. McKenna
 	5.79		11.5 R. McNaught	11.34	12.0 R. DeMartino
 	6.35		11.8 J. McKenna		11.42	12.3 R. Royer
 	6.35		11.3 B. Bois		11.483	12.5 K. Larson
 	6.469		11.5 K. Larson		12.2	12.4 J. Bortle
 	7.39		11.2 D. Kaiser		12.29	12.2 R. DeMartino
 	7.5		11.5 R. Royer		12.33	12.3 C. Predom
 	8.27		11.8 J. Griese		13.081	12.0 P. Schmeer
 	8.81		12.2 R. McNaught	14.101	12.2 P. Schmeer
 	9.14		11.9 A Pereira		14.2299	12.4 S. Knight
 	9.4		12.0 R. Royer		15.097	12.4 P. Schmeer
 						16.113	12.5 P. Schmeer

A "d" scale chart is being prepared and will be distributed as soon as it 
becomes available. Please continue to monitor this extremely interesting nova, 
and continue to call your observations in to Headquarters.

NOVA CENTAURI 1991

Although Nova Cen 1991 (see AAVSO Alert Notice 140) has faded somewhat, it is 
not fading as rapidly as had been expected, as these observations indicate: 
11.0 (R. McNaught); 10.61, 11.4 (R. McNaught); 11.8, 12.8: (D. Overbeek); 
15.1, 11.3 (W. Liller); 17.0, 113 (W. Liller).

Please continue to monitor this nova, and report your observations to 
AAVSO Headquarters.

The answering machine at Headquarters (617-354-0484) is kept on nights and 
weekends. Please call in your observations so we may relay them to the Central 
Bureau for Astronomical Telegrams.

Janet Mattei, who is away, and I thank you for your efforts and astronomical 
contributions!

Clear Skies! Good Observing!

Elizabeth O. Waagen
Senior Technical Assistant

Keywords:
AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484