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Special Notice #317: HST COS observing HS 0218+3229 2012 December 22 and SDSS J093249.57+472523.0 is probable next target

December 20, 2012: Further to AAVSO Alert Notice 471 ( and AAVSO Special Notice #315 (, HST COS is scheduled to observe the U Gem-type cataclysmic variable HS 0218+3229 on December 22:

                              HS 0218+3229  22 December 2012 06:07:48 through 10:17:53 UT

***PLEASE GIVE HS 0218+3229 TOP PRIORITY - YOUR OBSERVATIONS WILL BE CRUCIAL FOR THE HST SCHEDULING TEAM TO DECIDE TOMORROW whether to carry out the observations.*** HS 0218+3229 is 15.5V at minimum and 12.5V at maximum.

Coordinates for HS 0218+3229: R.A. 02 21 33.48  Dec +32 43 23.9 (2000.0)

The probable next HST COS target is the UG-type dwarf nova SDSS J093249.57+472523.0:

                                     SDSS J093249.57+472523.0  window: 2013 January 7 - 14

Please focus on SDSS J093249.57+472523.0 after the HS 0218+3229 HST observations are over. A more precise schedule of observations will be announced as soon as it is available. SDSS J093249.57+472523.0 is 17.9V at minimum and unknown at maximum.

Coordinates for SDSS J093249.57+472523.0: R.A. 09 32 49.58  Dec. +47 25 23.2 (2000.0)

As instructed in AAVSO Alert Notice 471, for CCD observers, simultaneous photometry [shortly before, during, and after the HST observations] would be ideal. B filter would be best for a light curve, although for the magnitude estimates, a V measurement would be best. An uninterrupted light curve would be better than cycling between filters. HS 0218+3229 is a reasonable visual target at 12.5-15.5V. SDSS J093249.57+472523.0 is most likely too faint for positive visual observations at minimum. If positive visual observations of either system are possible they are welcome, as are visual fainter-than observations fainter than magnitude 15.0.

Charts for both targets may be created using VSP ( When requesting a chart for HS 0218+3229, be sure to include the space after HS.

Please report observations as soon as possible to the AAVSO International Database as HS 0218+3229 and SDSS J093249.57+472523.0, respectively. If an outburst is detected, please report observations immediately. Many thanks!

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


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