The Farpoint Focus Mask Finder matches your telescope to the right Bahtinov mask in one step. Two ways to use it: enter your telescope’s tube outer diameter in millimeters or inches, or pick your telescope from the dropdown (191 catalog telescopes across 9 brands). For each scope you’ll get up to four mask options — Standard Bahtinov, Tri-Bahtinov for collimation + focus, and Hyperstar/RASA variants for SCT telescopes.

What the Finder Returns

• Standard Bahtinov — the classic single-pattern mask. Focus only. Available either scope-specific (fits one telescope precisely) or adjustable (fits a range of OTAs).
• Tri-Bahtinov — a three-pattern mask. Lets you check collimation at the same time as focus. Useful for SCTs and any scope where you adjust the secondary mirror.
• Hyperstar / RASA variants — for SCT telescopes used in Hyperstar or RASA imaging configuration, where the secondary mirror is replaced by a corrector and camera. These have a larger center cutout to clear that hardware.

How the Sizing Works

If you pick a known telescope from the dropdown, the Finder returns the exact mask SKU(s) sized for that scope. For SCT models with named-cluster fits (Celestron 6/8/9.25/11/14 SCT, Meade 8/10/12/14/16 SCT), there’s a scope-specific mask that fits more precisely than an adjustable. For Newtonians, Dobsonians, refractors, and Maksutov-Cassegrains, the Finder maps your tube OD to one of our 12 adjustable Bahtinov mask sizes (2.5” to 18” OTAs).

If you enter a tube OD directly, the Finder returns the adjustable mask that fits. Want the most precise fit? If your scope is in the dropdown, that’s the better path — scope-specific masks have the right cutouts for SCT corrector plates, Hyperstar assemblies, or specific dovetail orientations.

Outside the Bahtinov Range?

• Under 60 mm (finder scopes, guide scopes, very small refractors) — we don’t make Bahtinov masks below 60 mm. The Finder routes you to a contact form if you need one custom-built.
• Above 457 mm (18” OTAs and larger) — the Finder routes you to a contact form for a custom-order quote.

DSLR Camera Lenses

This Finder is for telescope masks. If you’re imaging with a DSLR camera lens, see our DSLR lens Bahtinov masks — available for 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm, and 82mm filter threads, plus Cokin P and Cokin Z square filter holders.

Browse the Mask Lineup

→ Browse all Bahtinov focus masks

Standard Bahtinov masks · Tri-Bahtinov masks · Adjustable Bahtinov masks