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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 140 (April5, 1991)
				
				
NOVA CENTAUR! 1991

AAVSO member William Liller of Vina del Mar, Chile, has used the Problicom 
photographic method to discover a nova in Centaurus at the following 
position (1950.0):

			R.A. 13h 46m 37.13s  Decl. -62deg 54' OO.O"

The nova was confirmed visually by Robert McNaught and spectroscopically by M. Hamuy
at Cerro Tololo Interamerican Observatory. The following observations have been
reported:

Mar	11 UT		<13	P. Camilleri, photographic
	17.389		<11	W. Liller, photographic w/ orange filter
	22.66		12.5	P. Camilleri, photographic
Apr	2.139		8.7	W. Liller, photographic w/ red filter
	2.143		8.7	W. Liller, photographic w/ red filter
	3.81		11.4	R. McNaught
	4.49		11.5	R. McNaught
	4.77		12.0	D. Overbeek

Please monitor this nova, using the accompanying finder chart from the AAVSO 
Variable Star Atlas and the accompanying AAVSO chart of RV Cen to estimate 
its brightness.

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

NOVA HERCULlS 1991

This bright nova is continuing to fade, as indicated by the following observations:

Mar	30.46UT		8.5 P. Sventek	Apr	2.46	9.9 D. York
	30.493		9.3 K. Larson		2.5	9.7 R. Royer
	31.25		9.5 M. Mattei		3.341	10.4 J.Bortle
	31.35		9.4 J. Griese		3.79	10.9 R. McNaught
	31.375		9.4 J. Bortle		4.216	10.7 J. Bortle
	31.4		9.2 E. Halbach		4.27	10.9 C. Predom
	31.46		9.4 P. Sventek		4.345	11.1 R. DeMartino
	31.5		8.9 R. Royer		4.37	10.7 J. McKenna
Apr	1.358		9.9 J. Bortle		4.396	11. C. Scovil
	2.394		10.6 C. Scovil		4.5	10.8 R. Royer - nova is red
	2.40		9.9 J. McKenna


Two series of photoelectric observations made by L. Snyder to search for fast 
photometric variations show modulations with an amplitude of 0.096 magnitude on 
March 30, and 0.061 magnitude on March 31. It was not possible to determine the 
modulation periodicity.

Please use the accompanying revised finder chart to continue to monitor this 
nova as closely as you can, and continue to call your observations in to 
Headquarters.

Many thanks for your efforts and astronomical contributions!

Clear Skies! Good Observing!

Janet A. Mattei
Director