THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 25 Birch Street, Cambridge, MA 02138 USA Tel. 617-354-0484 Fax 617-354-0665 http://www.aavso.org * * * AAVSO NEWS FLASH * * * Subject: 2138+43 SS CYG No. 446 June 2, 1999 ---------------------------------------------------------------------------- 2138+43 SS CYGNI - Observations Urgently Requested Observations of SS Cygni during its current activity are urgently needed. SS Cyg is presently at about visual magnitude 10.7, rising slowly over the past week from its minimum magnitude of 11.8. It is not known whether this brightening is the start of an outburst which will rise to maximum, or a mini-brightening which will not reach maximum brightness. Astronomers at Lawrence Livermore National Laboratory have until the end of June to make multiwavelength observations of SS Cygni in outburst (see AAVSO Alert Notice 257 for details of this campaign). The astronomers need several days to point some of the satellites involved, so complete and up-to-the-minute information on the star's behavior is essential to determine if a true outburst is occurring and if the outburst will last long enough to point the satellites and make observations. Please observe SS Cygni and REPORT YOUR OBSERVATIONS TO AAVSO HEADQUARTERS BY TELEPHONE OR EMAIL AS SOON AS YOU MAKE THEM WHILE THE STAR IS BRIGHTENING AND IS AT MAXIMUM. If it is at all possible, please don't wait until the next day to report them - even an hour or two or a single observation may be critical in evaluating the star's behavior. Once SS Cyg begins to fade, please report your observations daily until it returns to its minimum brightness. The AAVSO charts for SS Cyg may be obtained from our web site http://www.aavso.org or our anonymous ftp site ftp.aavso.org (198.116.78.5) in /charts Observers in the US may use our toll-free number (888-802-7827) to report their observations; email reports may be sent to observations@aavso.org. Your observations truly are crucial to the success of this observing campaign! Good observing! Elizabeth O. Waagen, Senior Technical Assistant on behalf of Janet A. Mattei, Director ____________________________________________________________________________ If you would like to contribute to AAVSO NEWS FLASH, please send observations of unusual variable star activity to: observations@aavso.org Those who wish to subscribe (free of charge) or unsubscribe to NEWS FLASH may do so by visiting the following web page: http://www.aavso.org If you would like data from the AAVSO International Database for research purposes, please send your request to: Janet Mattei, AAVSO Director, at aavso@aavso.org An archive of past issues of the News Flash is available at the following web page: http://www.aavso.org/newsflash/ We look forward to including your observations in future editions of AAVSO NEWS FLASH! ____________________________________________________________________________