Please note: The measurements are for the OUTSIDE DIAMETER of your telescope, not the optical aperture!
TS-Optics Bahtinov Masks for convenient and exact focusing of your Astro Images
The Bahtinov Mask is named after its inventor Pavel Bahtinov. This focusing tool enables precise adjustment of your Astro pictures to the focus plane of your telescope or camera lens.
Attaching the Bahtinov Mask to your telescope or lens is very simple. Each mask is supplied with 3 screws. Remove the plastic from the screws, put them through the designated holes and then pull the plastic covers back over the screws. Now you can attach the focusing mask to your telescope or lens and start focusing.
This is how focusing of your camera on your telescope or lens works.
♦ Attach the mask to your telescope and slew the telescope to a bright star.
♦ Turn on your camera and watch your selected star on the live view screen.
♦ If the image isn´t yet in focus, the central line of the Bahtinov pattern is shifted. Adjust your focuser until this very line sits exactly inbetween the other two lines.
♦ Now you have achieved optimal focus. Remove the mask from your optics and you can start the exposure of your object.