The Farpoint Solar Filter Finder matches your telescope to the right SSF Solar Filter SKU 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 tubes outside the 120–397 mm SSF range, the Finder routes you to the right next step.
1Enter your tube OD
Measure the outer diameter of your telescope's optical tube where the front objective is mounted.
2Or pick your telescope
191 catalog telescopes across 9 brands. Not listed? Use the tube-OD method on the left.
What the Finder Returns
- Recommended SSF SKU with link to the product page and price
- Tube OD range the SKU covers, so you can confirm the fit
- Alternates — up to two other SSF sizes that also fit your tube, in case your scope is between sizes
How the Sizing Works
Each SSF SKU number is the maximum tube outer diameter the filter is designed to fit. SSF-239 fits telescopes with a tube OD between 234 mm and 239 mm. The 5 mm fit window covers all current SCT and Maksutov-Cassegrain models within the same aperture class, plus most Dobsonians and refractors at that size.
Six additional sizes — SSF-172, SSF-188, SSF-207, SSF-239, SSF-316, and SSF-397 — fine-tune coverage for popular scope clusters like the Celestron 8″ SCT family and 11″ SCT family. When more than one SSF fits your tube, the Finder shows the closest match first and lists the others as alternatives.
Outside the SSF Range?
- Under 120 mm (finder scopes, guide scopes, very small refractors) — our small-aperture solar filter line is in design. The Finder routes you to a notification signup.
- 381–391 mm or above 397 mm — the Finder routes you to a contact form for a custom-order quote.