THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS 25 Birch Street, Cambridge, MA 02138 USA Tel. 617-354-0484 Fax 617-354-0665 INTERNET: aavso@aavso.org * * * AAVSO NEWS FLASH * * * Subject: Z Cam, HL CMa, MU Cen, CY Lyr, No. 299 V2051 Oph, ER UMa May 18, 1998 ____________________________________________________________________________ Z CAMELOPARDALIS The dwarf nova type (Z Cam subclass prototype) cataclysmic variable Z Cam is in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAY 14.0840 12.4 MKJ MAY 15.8750 11.0 SJZ MAY 14.0951 12.9 BRJ MAY 15.9577 11.1 BMM MAY 14.4382 12.3 POX MAY 16.00 10.9 GRL MAY 14.912 12.3 BOS MAY 16.1625 11.1 HSG MAY 14.9493 12.2 BMM MAY 16.8 11.2 VET MAY 15.003 12.8 DPA MAY 16.888 11.1 DPA MAY 15.01 12.3 GRL MAY 16.9549 10.8 BMM MAY 15.0743 12.4 MKJ MAY 17.0771 10.7 KMA MAY 15.0861 12.7 BRJ MAY 17.9479 10.8 BMM MAY 15.3194 11.7 SQN MAY 18.0715 10.8 KMA MAY 15.8 11.3 VET MAY 18.0903 11.0 BRJ MAY 15.81 11.4 GUN ----------------------------------------------------------------------------- HL CANIS MAJORIS The dwarf nova type (Z Cam subclass) cataclysmic variable HL CMa appears to be in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAY 04.3937 <13.7 SRX MAY 13.3486 11.4 SRX MAY 08.3903 <12.1 SRX MAY 17.4076 11.4 SRX ----------------------------------------------------------------------------- MU CENTAURI The dwarf nova type (SS Cyg subclass) cataclysmic variable MU Cen is in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAY 02.4208 14.7 SRX MAY 17.4556 13.3 SRX MAY 13.6153 <13.6 SRX MAY 17.721 13.4 OB MAY 16.7 <13.3 OB ----------------------------------------------------------------------------- CY LYRAE The dwarf nova type cataclysmic variable CY Lyr is in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAY 07.4375 <14.8 HSG MAY 15.9 13.0 VET MAY 10.003 <14.5 PYG MAY 15.9100 13.3 GUN MAY 14.2400 13.56 CCDV ZRE MAY 16.9 13.2 VET MAY 15.1118 13.2 BRJ MAY 17.1479 13.9 WEI MAY 15.2500 13.38 CCDV ZRE MAY 17.1979 13.1 WEI MAY 15.4340 12.8 SQN MAY 18.3060 13.52 CCDV ZRE MAY 15.81 13.2 GUN ----------------------------------------------------------------------------- V2051 OPHIUCHI The nova-like cataclysmic variable V2051 Oph is in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAY 17.0 <13.8 OB MAY 17.4875 13.6 SRX MAY 17.4729 13.5 SRX MAY 17.999 13.4 OB MAY 17.4806 13.6 SRX ----------------------------------------------------------------------------- ER URSAE MAJORIS The dwarf nova type (SU UMa subclass) cataclysmic variable ER UMa is in outburst, as indicated by the following observations: AAVSO Observer AAVSO Observer UT Mag. Initials UT Mag. Initials MAY 15.9542 <14.5 BMM MAY 17.9438 14.3 BMM MAY 16.1660 15.1: HSG MAY 18.0896 13.9 BRJ MAY 16.9514 <14.5 BMM ----------------------------------------------------------------------------- We thank the following contributors for the data that they have provided for this News Flash: BMM - M. Biesmans, Belgium OB - D. Overbeek, South Africa BOS - E. Broens, Belgium POX - M. Poxon, England BRJ - J. Bortle, USA PYG - G. Poyner, England DPA - A. Diepvens, Belgium SJZ - J. Speil, Poland GRL - B. Granslo, Norway SQN - L. Shaw, USA GUN - J. Gunther, France SRX - R. Subbings, Australia HSG - G. Hanson, USA VET - M. Verdenet, France KMA - M. A. Komorous, Canada WEI - D. Weier, USA MKJ - J. McKenna, USA ZRE - R. Zissell, USA Please monitor these and other variable stars closely and phone-in, fax, or e-mail your observations to the AAVSO. Good observing! Rebecca Pellock, Technical Assistant on behalf of Janet A. Mattei, Director ____________________________________________________________________________ Symbols may include: < = fainter than magnitude given (variable not seen) : = uncertain CCDV = Charge-coupled device with (V) filter 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 sending a message to: observations@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 We look forward to including your observations in future editions of AAVSO NEWS FLASH! ___________________________________________________________________________