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				AAVSO ALERT NOTICE 157 (May 28,1992)


The Central Bureau for Astronomical Telegrams (IAU Circulars 5526, 5528) has informed us 
of the photographic discovery of a probable nova in Scorpius by Paul Camilleri, Cobram, 
Victoria, Australia, on May 22.492 UT at photovisual magnitude 8.2. The precise 1950 position 
of the probable nova is:

			R.A. 17h 03m 42.69s	Dec. -43deg 11' 26.5"

Recent observations include:

Apr.	28.600 UT	<12	photovisual, P. Camilleri
May	22.492		8.2	photovisual, Camilleri
	23.511		8.3	photovisual, Camilleri
	24.371		8.3	visual, P. Williams, Heathcote, NSW, Australia
	24.425		8.4	visual, Camilleri

The accompanying 'aa' scale AAVSO chart shows the location of the probable nova. Please use 
this chart, along with the accompanying sequence for RS Sco, to make your estimates. Please 
telephone your observations in to AA VSO Headquarters, so we may inform the astronomical community.

Our congratulations to Paul on his latest discovery! 

2027 + 52 NOVA CYGNI 1992

Nova Cyg 92 continues to fade, and is presently in the mid-8th magnitude range. Accompanying 
is a revised "d" chart for N Cyg 92. Four of the comparison stars on the "d" chart dated 3/92 
have been measured photoelectrically by B. Skiff and the magnitudes adjusted. A fifth magnitude 
on this chart has also been revised. The revised comparison stars are:

		Old 	New 	Old	New	Old	New
		8.8	9.2V	11.2	11.3V	10.8	11.0
		9.7	10.1V	13.0	12.8V

Please use this revised chart to observe the nova. If you have made observations using any of 
the comparison stars whose magnitudes have been changed, please revise your estimates and 
re-submit them to AA VSO Headquarters, making sure to indicate that they are revised estimates.


Astronomers scheduled to observe the cataclysmic variables listed below with the Hubble 
Space Telescope (HST) and the International Ultraviolet Explorer (IUE) have requested our 
assistance in closely monitoring these stars and informing them of their behavior so they 
can observe them at the appropriate times.

1. Observations with HST

0749 + 22 U Gem and 0409-71 VW Hyi

For the next 6 months, astronomers will be interested in observing the white dwarf component of 
these close binary systems while the systems are in quiescence. Using the long-running AAVSO 
data base we have predicted the "best" times for the astronomers observations with HST. In 
order to confirm and/or revise these predictions, it is essential to know when U Gem and VW Hyi 
have outbursts from now until January 1993.

Please monitor these stars whenever they are observable, and call in your observations to 
Headquarters when either star has an outburst.

2318+17 IP Peg

A large consortium of astronomers will be studying the cataclysmic variable IP Peg with HST 
for a year, beginning in July. They would like to know when the outbursts occur as they plan 
to follow it through an outburst cycle. They are depending on you for earth­based monitoring 
and immediate notification of its outbursts.

Please monitor IP Peg whenever it is observable, and call in your observations to Headquarters 
when it has an outburst.

2. Observations with IUE

1137+72 YY Dra and 1129-11 Crt

Astronomers are planning to observe these two cataclysmic variables with the IUE in the 
coming year, beginning in June. They are depending on you for any alert to the rather 
infrequent outbursts of these stars, so they may schedule the IUE to obtain UV observations 
at critical times.

Please monitor these stars and inform Headquarters of any outburst activity.

0900-31 T Pyx

This recurrent nova, whose last outburst occurred in December 1966, is overdue for an outburst. 
Please monitor it closely, and call Headquarters when the eruption occurs, as astronomers are 
interested in observing it with the IUE at this time. Observers beware there is a near-by 
variable star possibly in the magnitude 13 - 15 range which has misled observers of T Pyx 
in the past!

If you need finder charts for the above stars please write to HQ and request copies, which 
will be sent free of charge. Your calls to HQ in connection with the above requests will be 
reimbursed by the astronomers, so please send in copies of pertinent telephone bills.

As always, your observations of these objects and immediate outburst information are vital to 
the scheduling of the satellites and the success of the projects. Please monitor the above-
mentioned stars closely and call in your observations of their outbursts to Headquarters. 
The answering machine (617-354-0484) is on nights and weekends for your convemence.

I would like to share with you an excerpt from a letter from an astronomer who has utilized our 
support services in his satellite research: "I am writing to convey my deepest gratitude for 
the indispensable observational ground-support your organization has provided 
and will continue to provide for my [HST] project. The recent information on the detailed 
outburst histories of VW Hyi and U Gem were absolutely essential to scheduling and carrying 
out my time-critical HST experiments successfully... Without your data support and continued 
monitoring by your ground-based observers, scientific progress in understanding cataclysmic 
variables would be well-nigh impossible..."

Your astronomical efforts truly ~ appreciated! Good observing!

Janet A. Mattei

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