How to use a Bahtinov Mask

A bahtinov focus mask is a tool for astrophotography to easily focus your camera to infinity. It works by diffracting incoming light into a predictable and recognizable pattern. With the mask attached, you'll be able focus to infinity within seconds, saving you set up time for nighttime photography. 

  1. If you are using a star tracker, first polar align your mount

  2. Use the camera’s live view screen to zoom in on a bright star (not a planet).

  3. Manually focus to get pretty close. The bahtinov mask fits over the front aperture of the camera lens

  4. Disregard any flying saucers. We’re supposed to refer to them as “cloud formations” per the outcome of the most recent meeting of the Astronomer’s Cabal. 

  5. Attach the Bahtinov Mask to the front of the lens or dew shield. Use the screws to hold the mask in place. 

  6. Adjust the focus ring so that the middle spike is centered between the other two. the bahtinov mask refracts light to make it easier to focus to infinity

  7. Snap a test shot and confirm the spike is centered.

  8. Remove the mask and start shooting.

  9. Repeat step 8. That one’s important.

  10. Did you remove the mask?

Using a bahtinov mask to focus is much easier than trying to focus on the stars by eyesight alone. It will cut down your set up time so you can spend more clear nights taking pictures of the stars. Check out our full collection of professional bahtinov masks here, or learn how to print a bahtinov mask template out at home. Be sure to Like and Follow Johannes Scientific on Facebook for more!