Farpoint FP404 Bahtinov Focus Mask for Telescopes with Dew Shield or Front End Diameter from 8.5" to 10.5"

Bahtinov Focus Masks... In 2008 an amateur telescope maker and astronomer ppublished an ingenious new way to easily focus your DSLR, webcam or CCD camera for taking astrophotos. The method is simple, very intuitive and the device has universally been named after the inventor. The Bahtinov Mask. Farpoint manufactures this *LIFESAVING* astrophotography tool out of virtually indestructable ABS plastic and comes in two major types and in a range of sizes. One mask is a general purpose mask designed to fit refractors and newtonian telescope. The other mask is designed to fit Schmidt Cassegrain telescopes. Both types of mask are available in a range of sizes to cover your needs.