Skip to main content


Special Notice #330: Next HST/COS targets are IR Com and BB Dor

February 2, 2013:  Further to AAVSO Alert Notice 471 (, the next HST/COS target is the SU UMa-type dwarf nova IR Com. HST/COS observations are scheduled for:

     IR Com   2013 February 8 00:38:46 through 05:57:49 UT

IR Com is an eclipsing SU UMa-type dwarf nova. According to observations in the AAVSO International Database, it reaches V magnitude 18-19 at minimum. IR Com can be as bright as 13.5 V at maximum.

Special Notice #329: Critical time for CV Campaign HST/COS target SDSS J100515.38+191107.9

January 29, 2013:  SDSS J100515.38+191107.9 is the upcoming target for the HST/COS CV Campaign (see AAVSO Alert Notice 471 and AAVSO Observing Campaigns page ( for details and related Special Notices). Dr. Gaensicke writes:

"We are now entering the critical phase before the HST observations of SDSS1005+1911, scheduled for

                              Jan 31, 2013 01:17:09 to Jan 31, 2013 06:24:00 UT

Special Notice #328: HST/COS observing U Gem 2013 January 30

January 29, 2013: Further to AAVSO Alert Notice 475 ( and AAVSO Special Notice #327 (, HST/COS will be observing the dwarf nova U Gem on

                                        2013 January 30 21:31:12 - 23:36:16 UT

Special Notice #326: Next HST/COS target is SDSS J100515.38+191107.9

January 24, 2013: Further to AAVSO Alert Notice 471 (, the next HST COS target is the SU UMa-type dwarf nova SDSS J100515.38+191107.9. HST COS is scheduled to observe it:

                                          SDSS J100515.38+191107.9 2013 January 31 01:17:09 through 06:24:00 UT

Special Notice #325: BB Dor monitoring requested for Swift and HST observations

January 21, 2013: AAVSO observations are requested of the SW Sex-type novalike variable BB Dor in support of one and possibly two sets of multiwavelength observations: Dr. Tomohito Ohshima (Department of Astronomy, Kyoto University) and colleagues have triggered Target of Opportunity observations with NASA's Swift gamma-ray burst satellite, and Dr. Boris Gaensicke (Warwick University) is hoping to observe BB Dor in the ultraviolet with HST.


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