Kunegunda Belle, Don Hoard and Steve Howell are observing two cataclysmic variables with Spitzer during the next couple of weeks. They request ground-based light curves spanning the observation intervals so that they can identify the state each variable is in during the Spitzer visits.
1. EX HYA (12:52:24.20, -29:14:56.0, AUID 000-BBT-323)
The observations for EX Hya are scheduled for:
2009-08-18 19:25:01.1 UT 3.6micron single exposure
2009-08-18 19:26:52.9 UT 4.5micron light curve
EX Hya is an eclipsing system with 98-minute period and normally resides about V=13. The eclipses are only a magnitude or so in depth.
2. DQ HER (18:07:30.20, +45:51:32.0, AUID 000-BCB-341)
The observations for DQ Her are scheduled for:
2009-08-23 03:25:13.8 UT 3.6micron single exposure
2009-08-23 03:27:36.5 UT 4.5micron light curve
DQ Her normally sits at V=14.5, but remember that this is a deeply eclipsing system (280 minute period) and during eclipse it will dip below V=18.
The researchers request that you obtain a time series light curve, preferably in V-band, starting at least one day prior to and continuing one day after the Spitzer visit to the appropriate field. Expose long enough to get signal/noise = 30 in each individual frame.
Charts may be created using VSP .
This AAVSO Alert Notice was prepared by A. Henden.
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