Farpoint Bahtinov Focus Mask, Small, FP405 , Telescope Focusing mask, fits 8.5 to 11.5" Diameter Telescope Tubes. Easy Focus for Astrophotography.

Bahtinov focus mask for small telescopes; fits telescopes with front end dew shield or tube from 8.5" to11.5" inch (216mm to 292mm) diameter. Simple to fit.
Bahtinov focus masks make focusing for astrophotography fast and easy. Ends the pain of struggling to find the best focus for your astrophotography images.
Works with all electronic imaging devices. Includes DSLR cameras, modified DSLR cameras, CCD astro-imagers, CMOS astro-images, video cameras, low light systems etc.
Use by simply placing the Bahtinov focus mask over the end of your telescope, record a quick image of a bright star, adjust focus and repeat two or three times until perfect focus is achieved.
Made in the USA by Farpoint Astro