Farpoint Adjustable Tri-Bahtinov Mask — 2.5" to 4.5" OTAs Nebula Bandpass for which FarpointAstro sells V-size

for which FarpointAstro sells V-size saddles

Any mount with a D-size (Losmandy-style) saddle — Losmandy

12″ — see product drawing

This filter blocks wavelengths shorter than about 420nm

and lands on your secondary

Farpoint Adjustable Tri-Bahtinov Mask — 2.5" to 4.5" OTAs Nebula Bandpass for which FarpointAstro sells V-sizeNot sure this is the right mask for your telescope? Use our Focus Mask Finder match your scope to the right Standard, Tri Bahtinov, or Hyperstar RASA mask. Adjustable Tri Bahtinov focus and collimation mask for OTAs from 2. 5" to 4. 5" front aperture. Sets onto the front of your telescope, gives you focus AND a collimation check from a single short exposure, and lifts off cleanly when you're done. The adjustable peg system fits any scope in this