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Special Notice #76: Support for HST observations of SDSS074545, update

October 29, 2007: We have been informed by Paula Szkody that HST observations of SDSS074545 have been tentatively scheduled for the night of 2007 October 31/Nov 01 UT (approximate JD 2454405.56). Observations are pending ground-based confirmation that this cataclysmic variable is not in outburst and is thus faint enough to safely observe with HST. This decision will be made on the afternoon of Wednesday, 2007 October 31 UT, and so observations are critically needed during the night of 2007 October 30/31 UT (JD 2454404.5).

For those participating in this campaign, please obtain one or more observations of SDSS074545 such that (a) you detect the variable with S/N = 10 and can confirm that it is faint, or (b) that you detect the m(vis) = 15.8 (V = 15.764) comparison star with S/N = 10, and can confirm that SDSS074545 is "fainter-than" this limit.

Observations prior to the 2007 October 31 HST scheduling decision are most critical, and please submit all observations made before that time as quickly as possible. Please continue to observe this object through 2007 November 02, so that the full observing window is covered.

SDSS074545 (SDSS J074531.92+453829.5) is located at

RA: 07 45 31.92 , Dec +45 38 29.5 (J2000).

An SDSS F-scale chart for this object may be plotted using VSP:

Please use the RA and Dec to generate charts -- the name "SDSS074545" may be used to submit data and view recently submitted observations, but it will not yet resolve in either VSP or VSX.

Please report all observations to the AAVSO as "SDSS074545" (AAVSO Designation 0738+45). Please report all observations as soon as you are able to do so.

Thank you for participating in this and other AAVSO observing campaigns!

This AAVSO Special Notice was prepared by Matthew Templeton.



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