I have a 48mm and a 52mm IDAS Light Pollution filters.
See the Hutech web site for further info. You can also see Ron Wodaski's review of these great filters on his web site. The 48mm does have 2 small scratch marks on the edge of the filter which have no effect on performance, especially if you will be using it for the small chip sizes of a CCD. I have been using it with my ST7 with no ill effects. The price of this filter is only $120 obo shipped, I am knocking off $20 for the scratches. The 52mm is in excellent condition, period. The price for it is $140 obo shipped. I will post images tomorrow...
Thanks for looking,