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Farpoint Astro Bahtinov Focus Mask for Celestron 11" SCT w/Hyperstar - FP412H


FarPoint Bahtinov Focus Mask for Celestron 11" SCT w/Hyperstar

Bahtinov Focus Masks are the brainchild of Pavel Bahtinov, a Russian amateur telescope maker and astronomer. This indispensable astrophotography tool is constructed from nearly indestructible ABS plastic. It provides an intuitive new way to simplify DSLR, webcam or CCD camera focusing for astrophotography.

Attach your camera to a Celestron 11" SCT and center on a reasonably bright star to achieve rough focus. Then "hang" the mask over the telescope's front aperture by using the plastic screws from the front of the dew shield. Then, take a short exposure. The image of the star will exhibit diffraction spikes. The "center" set will probably deviate to one side or the other, demonstrating defocus.

Adjust focus and re-expose the star to show the diffraction spikes again. Repeat this process until you get the central diffraction spike concentrated against the star and the other spikes. When you obtain a symmetrical pattern, you'll know you've obtained the highest possible focus. Take off the mask, center your desired object and take your images!