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Value of 4 filter BVRI photometry on LPV’s

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Value of 4 filter BVRI photometry on LPV’s

Fewer visual observers are recording data on long period variables.  There was a request to do CCD Photometry on these stars to allow transformation of the historical visual data to current CCD data.

Most recent CCD observers have chosen the B and V or V and I bandpasses for this task.  Is there significant benefit to do transformed 4 filter photometry on these stars?  VPHOT makes it easy to measure and transform images from two filters but it is quite clumbersome to do 4 filters.

 If it is worth doing 4 filters would BV combined with a subset of Sloan filters be better than BVRI?


Richard Sabo

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484