[Aavso-photometry] RE: Crud on Filters

[Michael Koppelman]

My filters which went bad it was only one side of the filter. This  
confirms what others had said and what Arne said in his talk about it  
being one of the glasses in the V and B filters. Arne suggested that  
perhaps anti-reflection coatings would stop this from happening  
because it isolates the glass in question from the air. This makes  
sense to me and makes me think I should spend the extra bucks and get  
AR coated filters. Does anyone have reason to believe this wouldn't  
work?

The "new" Schuler filters sound pretty good, too, but it doesn't  
sound like they will be available for a few months?

Michael