Gosky Bahtinov Focusing Mask for for Telescopes Dew Shield Front Diameter from 155-200mm(6.1inch-7.8inch)

It will take less time to achieve perfect focus with your new mask which mean you spend more time imaging photons rather than focusing them. Light weight so you wont upset the balance on your scope. The mask attaches securely to your scope using brass screws with soft transparent nylon cover to ensure the finish of your telescope is protected. Suitable for telescopes Dew Shield or Front Outer Diameter from 155-200mm(6.1inch-7.8inch) - For Compatible with 6" Skywatcher, Celestron Newton C6 SCT Etc. Bahtinov masks make focusing for astrophotography an easy task. Watch the two slanted areas create an "X" over the star. The vertical slits create a moving bar that is centered on the X when you are at focus.

Finderscope: Reflex. Objective Lens Diameter: 90 Millimeters. Brand: Gosky. Manufacturer: Everest. Date First Available: August 12, 2015. Is Discontinued By Manufacturer: No. Best Sellers Rank: #21 in Telescope Finder Scopes. Customer Reviews: 3.5 out of 5 stars 37 ratings 3.5 out of 5 stars. Item model number: QHAI039. : B013S1VZ8I. Item Weight: 6.4 ounces. Package Dimensions: 10 x 9.8 x 1 inches.