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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
                    INTERNET:  aavso@cfa0.harvard.edu
               Tel. 617-354-0484       FAX 617-354-0665


               AAVSO ALERT NOTICE 172 (May 18, 1993)


1908+01 NOVA AQUILAE 1993

We have been informed through the Nova Net and by the Central Bureau for 
Astronomical Telegrams that Tomohiro Hirayama (National Astronomical 
Observatory, Tokyo) reports that Minoru Yamamoto (Doi-cho, Okazaki-shi, Japan) 
photographically discovered a nova in Aquila at photovisual magnitude 7.6 on 
T-Max 400 film with a PO0 green filter taken on May 14.644 UT.  Yamamoto's 
discovery was reported to the Central Bureau for Astronomical Telegrams on 
May 15.  The presence of the nova was confirmed visually and photographically 
by several observers.  The nova was independently discovered by William Liller
(Vina del Mar, Chile) on May 13.351 UT on Tech-Pan film with an orange filter 
and using the PROBLICOM technique at photographic magnitude 8.7.  Liller's 
discovery was reported to the Central Bureau for Astronomical Telegrams on 
May 17.


The precise position of the nova (1950.0), reported via the Nova Net by Dave 
Balam (University of Victoria, Climenhaga Observatory), is:

         R.A. = 19h 10m 34.69s     Decl. = +01 degree 29' 14.0"

S. J. Austin and S. G. Starrfield (Arizona State University) and R. M. Wagner
(Ohio State University) report that "Optical spectra of Nova Aquilae 1993
... obtained with the Perkins 1.8-m telescope and CCD spectrograph on May 
17.35 UT ... confirm the identification as a 'Fe II class' nova in the early
post-maximum phase of its development."

Recent observations of N Aql 93 include: 
Apr 17.780 UT [10 ptg (Yamamoto); 26.244, [11.5 ptg (W. Liller, Vina del Mar, 
Chile); 28.802, [12 (P. Camilleri, Cobram, Victoria, Australia); May 13.351, 
8.7 ptg (Liller, independent discovery); 14.644, 7.6 ptg (Yamamoto, 
discovery); 14.647, 7.6 ptg (Yamamoto); 14.779, 7.6 (Y. Sakurai, Mito, Japan);
15.009, 7.6 ptg (M. Collins, Everton, Beds, England); 15.604, 7.9 (Yamamoto); 
15.648, 7.6 ptg (Yamamoto); 16.606, 8.0 (M. Yamada, Ishikawa, Japan); 16.640, 
8.0 (Yamada); 16.653, 7.9 (M. Watanabe, Toyama, Japan); 16.694, 7.8 ptg 
(S. Kiyota, Tsukuba, Ibaraki, Japan); 17.194, 8.0 (M. Baldwin, Butlerville, 
IN); 17.215, 8.0 (Baldwin); 17.246, 8.2 ptg (Liller); 17.279, 7.90 V (D. 
Kaiser, Columbus, IN); 17.306, 7.90 V (Kaiser); 17.406, 7.6 (D. Williams, 
Indianapolis, IN); 18.028, 8.1 (P. Schmeer, Bischmisheim, Germany); 18.055, 
8.058 V (M. Mikolajewska and B. Wikierski, N. Copernicus Observatory, Torun, 
Poland); 18.063, 8.3 (G. Mavrofridis, Nikea, Greece), 18.096, 8.22 V (H. 
Mikuz, Ljubljana, Slovenia); 18.201, 8.2 (C. Scovil, Stamford, CT).

A finder chart for 1908+01 N Aql 1993 from the AAVSO Variable Star Atlas is 
distributed with this alert notice.  Until you receive your copy by mail, 
please use the following SAO stars to observe the nova.  These SAO stars are 
identified on the AAVSO Variable Star Atlas as comparison stars for other
variable stars in the region of the nova.  Visual magnitudes are from AAVSO 
charts and the Atlas.

           m(v)    R.A. (1950)        Dec (1950)
SAO 124189  8.1   19 00 18.530       +01 41 53.03
SAO 124242  8.4      02 33.392           31 55.64
SAO 124438  8.9      12 38.634           27 49.68
SAO 124439  9.2      12 39.295           19 17.16
SAO 124460  8.8      14 32.759       +02 08 01.75
SAO 124498  8.6      16 38.608           08 23.60

When you receive the chart, please use it to observe the nova, and telephone 
your observations to AAVSO Headquarters, so we may inform the astronomical 
community.  Please indicate which comparison stars you have used in making
your estimates.

Congratulations to M. Yamamoto on his discovery!


BRIGHTENING OF 1556-40 EX LUPI

The irregular variable EX Lup has brightened from its normal minimum magnitude 
of approximately 13.7, and is presently quite active.  Recent observations by
W. Albrecht (Pahala, HI) and A. F. Jones (Nelson, New Zealand) (IAU Circular
5791) show that EX Lup has brightened from 13.6 on Mar 26.634 (Albrecht), to 
12.9 on Apr 1.598 (Albrecht) and 12.8 on Apr 2.68 (Jones), to 11.4 on May 
13.70 (Jones).  Photometry by A. C. Gilmore and P. M. Kilmartin (Mt. John
Observatory, New Zealand) include May 1.54 UT, 12.27 V; 9.51, 12.81 V; 13.53,
11.58 V (IAU Circular 5791).

The AAVSO light curve of EX Lup from 1985 to 1989 shows the star quiet, with 
two or three possible brightenings indicated by single observations.  The 
light curve from 1989 to the present shows scatter in the observations, 
indicating activity on the order of one to one-and-a-half magnitudes, but no 
magnitudes brighter than 12.4. 

Enclosed is an AAVSO finder chart of EX Lup.  Please monitor this interesting 
star closely and report your observations to Headquarters. 


REVISION OF REQUEST TO MONITOR 2138+43 SS CYGNI AND 1014+20 AD LEO 

Observers are reminded of the request (see AAVSO Alert Notice 171) from 
astronomers observing with the Japanese x-ray satellite ASCA for both visual 
and photoelectric observations of the dwarf nova-type cataclysmic variable 
SS Cyg and the flare star AD Leo.  

The observation interval for SS Cygni has been revised, so that both stars 
will be observed during the week of May 24.  Please monitor these stars 
closely in the coming weeks and inform Headquarters by telephone of their 
behavior, particularly if you observe SS Cyg brightening and/or you observe 
a flare of AD Leo.


1719-23  NOVA OPHIUCHI 1993

N Oph 93 (see AAVSO Alert Notice 170, 171) has been continuing to fade 
rapidly, and is presently at about magnitude 13.0.  As it fades below 13.4, 
observers are requested to use the lettered sequence on the accompanying
AAVSO chart to observe N Oph 93 and to report their observations to 
Headquarters.


0947+69 SN 1993J in NGC 3031

This bright supernova (see AAVSO Alert Notices 169, 170, 171) is continuing 
to fade, and is presently at approximately magnitude 12.6.  Please continue 
your close monitoring of this supernova, and indicate which comparison stars 
you have used and from which AAVSO Alert Notice they have come when reporting 
your observations.  


The answering machine (617-354-0484) in on nights and weekends for your 
convenience.

Janet Mattei, who is in California attending a meeting, and I thank you for 
your valuable observations and your efforts.

Clear Skies and Good Observing!


Elizabeth O. Waagen
Senior Technical Assistant