[garymck (Gary)]

Hi,

after purchasing a complete set of Baader imaging filters I found when unpacking them and fitting them to my filter wheel that the blue filter had scratches on the non coated side of the filter (see pic). The suppliers reply is copied below:

"many thanks for your patience! I got the answer from Baader and they told us, that this small scratch (Baader think its more a grease spot which can be cleaned)have no effect to the image. Very small spots can be easily eliminated by a flatfield image. Baader makes only an exchange of the filter if we can give them a proof, that the filter makes problems with the image, even if the flatfield is subtract from the lights."

I other words, if you buy a new Baader filter, and it is scratched, Baader will not replace the filter unless you can prove that image calibration can't fix it.

I think that this is a rubbish policy new filters should not have scratches!!!

BTW I tried cleaning the "grease spot" to no effect - tried anything from windex to acetone.

cheers
Gary