FP410RT Tri-Bahtinov Focus and Collimation Mask for Celestron 8" RASA

The Tri-Bahtinov Mask is an advanced version of the Bahtinov mask that allows for even more precise adjustments and can also be used as a collimation tool



Tri-Bahtinov Focus and Collimation Mask for Celestron 8" RASA- For the Celestron RASA 8" telescope, is an ingenious new way to easily focus a telescope. Pavel Bahtinov, a Russian amateur telescope maker and astronomer, created this simple, very intuitive method and the device has universally been named after him: The Bahtinov Mask.

Tri-Bahtinov Mask for Celestron 8" RASA

Tri-Bahtinov Mask for Celestron 8" RASA based off the classic Bahtinov mask: it allows to focus a bit more objective compared to visual star focusing.

The Bahtinov will produce Cross-shaped stars, with one clear line that moves along the cross as you focus. When the line is centered on the cross, you should have achieved perfect focus.

What is the Tri-Bahtinov?

It essentially three Bahtinov masks in one, rotated over 120 degrees. It gives you three lines and three crosses to check collimation, along three axis simultaneously.

In addition to focusing, the tri-Bahtinov so also indicates collimation status along three axis.

This is interesting for e.g. Schmidt-Cassegrain telescopes, where the collimation is done by push-pull screws of the secondary mirror along three axis.

When you position the tri-Bahtinov alongside these axis, it will give you insight not only per axis of the focus but also how different these focus points are for each axis.

Bahtinov mask is a less expensive method of getting focus on objects in the night sky compared to a standard motor focuser.

With the right mask and setup, it’s easy to get crystal clear focus on a star in less than 90 seconds.