Special Notice #373: Comparison star changed for HD 15407A

October 24, 2013: HD 15407A is one of the targets in the current observing campaign by Huan Meng and Dr. George Rieke (runs through December 2013; see AAVSO Alert Notice 482). The very nearby star marked 96 (HD 15407B, AUID 000-BKY-170) was selected as the comparison star for this target. However, it has been found that the published magnitude of this star is questionable, and the astronomers have withdrawn it as the comparison.

In the field of HD 15407A are a 95 (AUID 000-BKY-169) and a 102 (AUID 000-BKY-171). Please use these stars as comparisons for HD 15407A. Do not use the 96. Details regarding the 95 and 102 may be found in the Field Photometry table for HD 15407A from the AAVSO Variable Star Database. To see this table, create a chart for HD 15407A using the AAVSO Variable Star Plotter (VSP) and select the photometry table option.

If you have used the 96 - or any stars other than the 95 or 102 - as comparison stars for HD 15407A, please re-reduce your data using the 95 and 102, remove your old observations from the AAVSO International Database, and submit the re-reduced data. If you need assistance to remove your old observations, please let us know and we will be happy to help.

The astronomers recommend keeping an eye on the 96, and measuring and reporting its brightness, too. It is likely not variable, but additional measurements of its brightness will help ascertain that for certain and will allow basic information on the star to be updated.

Coordinates (2000.0):
HD 15407A   R.A. 02 30 50.66   Dec. +55 32 54.2
95                 R.A. 02 30 59.03   Dec. +55 42 22.7
102               R.A. 02 30 15.88   Dec. +55 39 20.9

If you have any questions about this, please let us know. Sincere thanks go to Gordon Myers (MGW, Hillsborough, CA) for alerting us to the discrepant published magnitude of the 96.

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



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