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			THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 
				2S Birch Street, Cambridge, MA 02138 USA 
				BITNET: aavso@cfa8 SPAN: nssdca::cfa8::aavso
					Tel. 617-354-0484 FAX617-3S4-0665
					
					
				AAVSO ALERT NOTICE 143 (May 3, 1991)

MAJOR CAMPAIGN ON THE FLARE STAR 101420 AD LEONIS

A major campaign has been organized by astronomers at Havard-Smithsonian Center 
for Astrophyics to observe the flare star 101420 AD Leonis (RA = 10h 16m 52s, 
Dec = +20deg 07' 17", 1950) on May 07, 08, and 09, 1991, with the Hubble Space 
Telescope, IDE, ROSAT, and GINGA satellites, the Very Large Array and Arecibo 
radio telescopes, and ground-based facilities. The purpose of these multiwavelength 
observations is to provide a comprehensive study of the dynamics and energetics 
of stellar flares. AD Leo has flare activity lasting from about a minute to many 
minutes. Flares are more prominent in shorter wavelengths.

We have been invited to participate in this major campaign by providing worldwide 
coverage of visual observations. If possible, please observe AD Leo continuously 
for periods of 10 to 15 minutes, as often as you can during the nights of May 01, 
08, and 09. When reporting your data please give VERY accurate timing of your 
observations (to four decimals places of the JD), particularly if you observe 
flaring activity, i.e., brightening. When reporting the date and time of your 
observations of non-flares in your monthly report, please use the following format:
Example: 10 minutes of observations on May 07, between 12:00 (midnight) GMAT 
and 12:10 GMAT: 2448384.5000-.5167

Photoelectric photometry is very much recommended in U, B, and V. For standardizing
the photometry the following stars have been selected by the project astronomers 
as standards:

	SAO 81296 (RA. = 10h 17m 09s, Decl. = +20deg 39' 21", mv = 8.4) and
	SAO 81313 (RA. =  10h 19m 11s, Decl. = +20deg 18' 23", mv = 8.93).

Please use the accompanying AAVSO "b" scale chart of AD Leo for your observations. The
standard stars for photometry are also shown on it.

SUPERNOVA 1991T IN NGC 4527

Recent observations of this supernova.include:
Apr	18.049 UT 	12.5 (P. Schmeer, Bischmisheim,			23.8632 11.8 (Ripero)
					Germany)			23.872 	11.7 (Schmeer)
	19.8424 11.5 (F. Pujol, Madrid, Spain)				24.0944 11.3 (Lubcke)
	19.8424 12.0 (J. Ripero, Madrid, Spain) 			24.1486 11.3 (Lubcke)
	19.8944 11.1 (D. Rodriguez, Madrid, Spain) 			24.872 11.5 (Schmeer)
	20.8424 11.5 (T. Lozano, Madrid, Spain) 			25.144 11.5 (CCD PEP (V), Smith)
	20.8424 11.5 (Pujol)						26.17 11.0 (R. Royer, Lakewood, CA)
	20.99 	11.8 (A. Peretra, Cabo da Roca,				27.21 11.3 (Royer)
					Portugal)			28.0958 11.3 (Lubcke)
	21.44 	11.5 (C. Stephan, Sebring, Ft.) 			28.25 11.3 (Royer)
	21.8424 12.0 (Ripero)						29.1 11.3 (Steffey)
	22.1243 11.6 (G. Lubcke, Middleton, WI)				29.25 11.3 (Royer)
	22.132 	11.6 (P. Steffey, Daytona Beach, FL) 			30.1 11.1 (Steffey)
	22.9048 12.0 (Rodriguez)					30.47 11.49 PEP (V), (A. Gilmore,
	23.097 	11.4 (Steffey) 						Mt. John Universicy Obs.)
	23.16 	11.7 (CCD PEP (V), H. Smith,				May 1.886 11.6 (Schmeer)
					Michigan State Universicy)


Accompanying is an AAVSO "e" scale chart of'this supernova.


NOVA HERCULIS 1991

Recent visual observations include:

Apr	18.086 UT	12.7 (P. Schmeer, Bischmisheim, Germany) 
	19.2		13.0 (E. Halbach, Estes Park, CO)
	21.088 		13.0 (Schmeer)
	22.079 		13.1 (Schmeer)
	22.17 		12.7 (A. Pereira, Cabo da Roca, Portugal)
	23.33 		13.2 (J. McKenna, Upper Montclair, NJ)
	24.5 		13.3 (Halbach)
	26.31		13.5: (R. DeMartino, West Haven, CT)

Accompanying is an "e" scale chart of N Her 91 with additional photoelectric 
magnitudes provided by T. Harrison, Mt. Stromlo Observatory.

NOVA MENSAE 1991 IN THE IARGE MAGELIANIC CLOUD

Recent observations include:

Apr	19.98 UT 	11.8 (photographic minus UV fitter,		24.975 9.1 (ptg minus UV filter, Liller)
	21.04		10.4 (ptg minus UV filter, Liller) 		25.7 9.3 (Overbeek)
	21.99		9.8 (ptg minus UV filter, Liller) 		26.7 9.3 (Overbeek)
	22.985		9.5 (ptg minus UV filter, Liller) 		28.975 10.2 (ptg minus UV filter, Liller)
	23.76		8.8 (T. Cooper, Benoni, S. Africa) 		30.37 11.48 (PEP (V), A. Gilmore,
	24.011		9.3 (ptg minus UV filter, Liller)			Mt. John U. Obs., New Zealand)
	24.73		9.2 (Cooper)					30.984 11.3 (ptg minus UV filter, Liller
	24.77		9.0 (D. Overbeek, Edenvale, S.Africa) May 	1.34 11.95 (PEP (V), Gilmore)

Accompanying is an AAVSO "d" scale chart of N Her 91.

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

Thank you very much for your efforts and astronomical contributions.

Clear Skies! Good Observing! Flares of AD Leo!

Janet A. Mattei
Director