TS-Optics Tri Bahtinov Mask for Celestron RASA 8 Inch

TS-Optics Bahtinov masks for easy and precise focusing of your astro images

The Bahtinov mask is named after the inventor Pavel Bahtinov. This focusing aid allows clear focusing of astro images in the focus of your telescope or with a camera lens. Tri-Bahtinov masks are three Bahtinov masks in one, rotated by 120 degrees. It gives you three lines and three crosses to check collimation along three axes simultaneously. So besides focusing, the Tri-Bahtinov mask also shows the collimation status along the three axes.

This is how focusing the camera works:

Put the mask on the telescope and point it at a bright star.

Switch on the camera and observe the constellation on Live View or on the computer.

If the image is not exactly sharp, the central line is shifted. Adjust the focuser until the central line runs exactly through the center of the star.

You have now achieved optimum sharpness. Remove the mask from the telescope again and you can start exposing the image.

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