When it comes to the cleanliness of their telescope's optics, Astronomers can be rightfully meticulous. As dust is so ubiquitous, it is nearly impossible to keep it off the telescope's optics completely. But you don't have to let dust reach your optics between observing sessions. Proudly manufactured in the USA, Astrozap dust cover material consists of a blend of cotton and nylon. A sewn elastic strap allows this dust cover to fit securely over a Newtonian telescope's open end, protecting the primary and secondary mirrors from dust accumulation for sharper images.