I purchased this some time ago from astromart and find that I haven't used it. It's in excellent condition. Looking to recover my investment of $50 shipped or best offer. Money back less shipping of not satisfied. Thanks for looking.
What is this for? This filters out ultra-violet light, and helps eliminate blue halos around the brighter stars in your astro photographs. This is a 72mm filter, but can be adapted to lenses with smaller filter sizes by an inexpensive step-up ring.