October 17, 2007: Further to AAVSO Special Notice #73, "SN 2007le in NGC 7721", a comparison star sequence has now been added to the AAVSO Variable Star Plotter (VSP). The sequence by A. Henden was obtained at SRO based upon a single night of data; the calibration is estimated to have a zero-point accuracy of approximately 0.03 magnitudes.
This type-Ia supernova is still believed to be prior to maximum light, and should be observable while still bright. However, it lies well within the bright spiral galaxy NGC 7721, and the field is thus heavily contaminated by background light from the galaxy itself. This will make accurate photometry of this object very difficult when it goes into decline.
An image of the supernova taken at SRO may be found at: http://www.aavso.org/tmp2/sn2007lev.jpg
Charts for this object may be plotted with VSP: http://www.aavso.org/observing/charts/vsp/index.html?pickname=SN%202007LE
Please report observations of this supernova to the AAVSO as "SN 2007LE" (AAVSO Designation 2333-07).
This AAVSO Special Notice was prepared by Matthew Templeton.
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