I have found a new never used skyglow filter. It was bought years ago by myself but I missplaced it and it was forgotton about. This is a the heavy screw on the back of the SC scopes filter and then it has threads on it. Don't remember how much it cost but I don't have a SC it would fit so------. Make me an offer if you want. Will take a picture of it upon request. It is a good filter for city lights blocking 99%. Can be used in photography but I am thinking it is better suited for visual work.
Mike