[Aavso-photometry] Filters to minimize differential extinction effects

[Tom Krajci]

I'm slowly learning about filtered photometry, but for years my bread 
and butter work has been unfiltered.

I know that my unfiltered data may capture lots of photons, compared to 
ye olde V filter bandpass (or other Johnson-Cousins filter bandpass):
http://www.astrodon.com/custom/_2e2a/content/files/SchulerUVBRIYel.jpg

But I can have significant problems with differential extinction for 
comp and target stars with poor color match.

Is there a filter type (inexpensive, easy to obtain) that provides a 
larger bandpass than Johnson-Cousins, that is considered scientifically 
valid and useful in the amateur science/photometry community?  I want to 
try and strike a balance between gathering lots of photons, and reducing 
differential extinction problems.  (Some sort of minus-blue filter perhaps?)

Thanks in advance,
Tom Krajci
Cloudcroft, NM

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Tom Krajci
Cloudcroft, New Mexico
http://picasaweb.google.com/tom.krajci

http://overton2.tamu.edu/aset/krajci/

Center for Backyard Astrophysics (CBA)
http://cbastro.org/ CBA New Mexico

American Association of Variable Star
Observers (AAVSO): KTC http://www.aavso.org/
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