TRI-Bahtinov Focus Mask - Celestron 52° FOV L-Enhance is a narrow tri-band

L-Enhance is a narrow tri-band filter

Red LED flashlight features three brightness levels to preserve your night vision

you can make tension adjustments to keep the phone firmly in place

Your finder is now aligned and should not require realignment unless it is bumped or dropped

and weighs 11 lb

TRI-Bahtinov Focus Mask - Celestron 52° FOV L-Enhance is a narrow tri-bandWhat is the Tri Bahtinov? Essentially three Bahtinov masks in one, rotated over 120 degrees. It gives you three lines and three crosses to check focus and 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