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Special Notice #236: HST observations scheduled for SDSS074545

March 4, 2011: Further to AAVSO Alert Notice 431, Dr. Paula Szkody, University of Washington, informs us that the time of the HST observations of SDSS074545 has been set for 5:22-9:32 UT on 2011 March 13. This is Saturday night March 12/13. The ground observations to confirm that the object is not in outburst - and allow the HST observations to take place - will then need to take place on Friday, March 11/12.

Please continue to make one observation per night between now and March 10, and more frequent observations Thursday, March 10/11, through Saturday, March 12/13, and then nightly observations again until the end of March.

It is extremely important that we know whether SDSS074545 is down as early in the evening of March 11/12 as possible, so please submit your observations to the AAVSO as soon as you make them using the name SDSS074545.

In the event of an outburst, please contact the AAVSO immediately.

CCD observers are asked to use filters during observations if available; V filter is preferred, but B,Rc, and Ic may also be used. At least magnitude 15.8 needs to be reached (SDSS074545 itself should be magnitude ~19). Please refer to AAVSO Alert Notice 431 for additional instructions for CCD observers.

Coordinates: R.A. 07:45:31.92 , Dec +45:38:29.5 (J2000)

Charts may be created using the Variable Star Plotter (VSP):

Your observations are critical to the success of these HST observations. Many thanks for your efforts and contributions!

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


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