Bahtinov Style Focus Masks

A Bahtinov style focus mask makes focusing your telescope for astrophotography quick, easy, and definitive.

Devised by amateur astrophotographer Pavel Bahtinov and released in to the public domain. The mask creates a diffraction pattern on a nearby bright focus star that provides feedback as to wether focus is front focused, back focused, or spot on (see photos).


  1. Faster than software methods like FWHM, brightest pixel etc....

  2. Works even in poor atmospheric seeing conditions.

  3. Accurate: The difference in focus knob movement of the three images to the right is fractions of a millimeter this is a very sensitive method.

  4. Definitive: You know from the feedback the mask provides that you have achieved proper focus. So you can cross focus problems off the long list of things you have to worry about when taking long exposure astro-photographs.

Features of Lumensa Bahtinov style focus masks.

  1. 100% No quibble money back guarantee.

  2. Our focus masks are laser cut from durable and flexible plastic and are made to last.

  3. Two nylon screws provide an easy non marring way to set the mask on the telescope for focusing.

  4. Our masks are priced affordably to bring high quality laser cut focus masks to as many people as possible.

  5. Sizes listed below reference the clear aperture overall dimensions of the mask is larger to be able to set the mask on the outer diameter of the telescope.

  6. We will custom design and cut a mask for any telescope not listed at no additional charge. Price is based on final size contact us with your needs for a precise quote.

  7. Download free templates if you would like to cut your own.

Our 80 mm Bahtinov Style Focus Mask

Front focus: central spike is lower than midpoint of star

Back focus: central spike is higher than midpoint of star

Focus is spot on here the central spike is dead center at the midpoint of the star

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Yeah the mask you sent me, I received Wednesday. Tried it out on my AP 130 and my Canon XTi camera. I could not believe how quickly I achieved focus. I'm going to be astromarting my other focus aids this one is a killer. Oh yeah forget about FWHM you don't need it. :)

                                                                                                            Dwight Bogan Phoenix, AZ