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Alert Notice 234: Rare outburst of 1858+42 V493 Lyrae AND Second set of observations scheduled in international observing campaign on 1913+49 AM Herculis

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

AAVSO ALERT NOTICE 234 (December 20, 1996)

RARE OUTBURST OF 1858+42 V493 LYRAE

We have been informed by G. Hanson, Cave Creek, AZ, of the rare outburst of
V493 Lyrae [R.A. 18h 59m 58s, Decl. +42o 50.4' (1950)].  Recent observations
of V493 Lyr include:

Dec. 14.71 UT, 14.7, J. Pietz, Erftstadts, Germany; 15.7611, 14.5 CCD, L. T.
Jensen, Farum, Denmark; 14.76, 14.7, Pietz; 18.0785, 13.8:, G. Hanson, Cave
Creek, AZ; 15.752, 14.1, Jensen; 19.0938, 13.7:, Hanson (Pietz and Jensen via
vsnet).

Three confirmed outbursts of V493 Lyr have been recorded in the AAVSO
International Database since the star was added to the AAVSO visual
observing program in August 1993.  Outbursts appear to last approximately
10 - 16 days.  The last outburst of V493 Lyr recorded in the AAVSO
International Database was in November 1995, when it reached visual
magnitude 13.6 at maximum.  There are also a few unconfirmed single
observations showing V493 Lyr around magnitude 14.

Accompanying is a 'd' scale AAVSO preliminary chart for V493 Lyr.  Please
monitor this star closely throughout its outburst and afterwards, and report
your observations to AAVSO Headquarters.

SECOND SET OF OBSERVATIONS SCHEDULED IN INTERNATIONAL OBSERVING CAMPAIGN
ON 1813+49 AM HERCULIS

As mentioned in AAVSO Alert Notice 218, 1996 marks the 20th anniversary of the
discovery of the magnetic cataclysmic variable AM Her [R.A. 18h 14m 59s,
Decl. +49o 50.8' (1950)].  The first phase of the international multi-satellite,
multi-observatory, multiwavelength observing campaign organized to celebrate
this anniversary (discussed in depth in AAVSO Alert Notice 218) has been
carried out by Dr. Boris Gaensicke, Universitaetssternwarte Goettingen, Germany,
and his colleagues around the world.

A second set of observations, with the Hubble Space Telescope, has been
scheduled by Dr. Gaensicke and his colleagues for January 3 - 6, 1997.

Presently, AM Her is in its high state, to which it has returned after being
in its low state for several weeks this summer.  Please monitor AM Her closely
from now until the end of January, and report your observations to AAVSO
Headquarters, especially if you see AM Her going into its low state, so we
may alert the astronomers involved in this international campaign.  Please use
the AAVSO preliminary 'd' and 'f' scale charts of AM Her issued with AAVSO
Alert Notice 218
.

CHARTS AVAILABLE ON AAVSO FTP SITE AND AAVSO HOME PAGE

Chart links are obsolete; 11/2013 create charts using VSP at http://www.aavso.org/vsp

We have prepared electronic copies of the AAVSO charts of AM Her and V493 Lyr
mentioned in this Alert Notice.  They are available from our FTP site in the
following directories:

AM Her:          ftp.aavso.org (198.116.78.2), in /pub/alert218

V493 Lyr:        ftp.aavso.org (198.116.78.2), in /pub/alert234

The charts also be accessed through our Web site at the following address:

                         http://www.aavso.org

The answering machine at AAVSO Headquarters is on nights and weekends for your
convenience.  Please call our charge-free number (800-642-3883) to report your
observations.  If you are cut off when you telephone in your observations,
please wait a few minutes and call back to complete your call.  We have learned
that if someone calls to leave observations on the answering machine and while
they are speaking someone else calls, the first person may be cut off.  We
also encourage observers to send observations by fax to 617-354-0665 or by
e-mail through the Internet to observations@aavso.org.  We would appreciate it
very much if you would report your observations in Universal Time.

Many thanks for your valuable astronomical contributions and your efforts.

Happy New Year!
Good observing!

Janet A. Mattei
Director

Note of thanks:  My sincere thanks to Elizabeth Waagen, my Senior
Technical Assistant and the AAVSO staff who published and mailed out the
Alert Notice 233 while I was away working on collaborative Hipparcos
projects and preparations for our 86th Spring Meeting on Variable Stars:
New Frontiers in Sion, St. Luc, Switzerland.

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