Bahtinov Focus Masks
22 products
22 products
Not sure which mask fits your telescope? Try our Focus Mask Finder — match 191 telescopes to the right mask: Standard Bahtinov, Tri-Bahtinov, or Hyperstar/RASA variants.
Farpoint Bahtinov Masks are the fastest, most reliable way to achieve perfect telescope focus for astrophotography. Each mask is precision-cut from virtually indestructible ABS plastic and made in the USA. Simply place the mask over your telescope's aperture, point at a bright star, and adjust your focuser until the central diffraction spike aligns with the X-pattern — sharp focus in under 90 seconds.
Telescope-Specific Bahtinov Masks
These classic Bahtinov masks are designed for specific telescope models — Celestron SCT and Classic series (6" through 14"), Meade SCT (8" through 14"), Sky-Watcher Maksutov, ASA astrographs, Celestron RASA, and the ZWO Seestar S50. Each mask is sized precisely to your telescope's aperture for an exact fit. If you own multiple telescopes or want a mask that fits a range of sizes, see our Adjustable Bahtinov Masks instead.
How It Works
The slits in a Bahtinov mask create a distinctive diffraction spike pattern on bright stars. As you adjust the focuser, the central spike moves through the X-pattern — when it's perfectly centered, you're in focus. This works with any camera setup: DSLR, CMOS, or CCD. The technique is far more precise than eyeballing focus and far less expensive than a motorized focusing system.
Choosing the Right Bahtinov Mask
Three things decide which Farpoint focus mask is right for you:
- One telescope, exact fit — Telescope-Specific Bahtinov. If you image with a single scope, a model-specific mask sized to your exact aperture gives the cleanest diffraction spikes and the most secure fit. Browse the telescope-specific masks on this page.
- Multiple scopes or an odd size — Adjustable Bahtinov Mask. One adjustable mask expands to fit a range of tube diameters, so it follows you across several telescopes or fits an OTA we don't make a dedicated mask for.
- Focus and collimation — Tri-Bahtinov Mask. The Tri-Bahtinov adds a three-way spike pattern that reveals both focus and collimation error at once — the choice for fast astrographs and imagers chasing the tightest possible stars.
To size any mask, measure the outside diameter of your telescope's optical tube or dew shield, or let the Focus Mask Finder match your exact model for you.
Who Uses Bahtinov Masks
- Astrophotographers — precise focus is critical for tight star shapes across your imaging field, whether you're shooting from a backyard observatory or a dark sky site in the Texas Hill Country, the Appalachians, or California's Central Valley
- Visual observers — the same diffraction spike technique works for visual astronomy, giving you the sharpest views through any telescope
- Star party regulars — Bahtinov masks are a staple at star parties and astronomy club gatherings across the country, from desert sites in Arizona to Great Lakes events in Michigan and Wisconsin
- Smart telescope owners — our ZWO Seestar S50 Bahtinov Mask PRO system brings precision focusing to the latest generation of smart scopes
Looking for more advanced focusing with built-in collimation checking? See our Tri-Bahtinov Masks for the ultimate focus and alignment tool.
Bahtinov Mask FAQ
What is a Bahtinov mask?
A Bahtinov mask is a focusing aid that fits over the front of your telescope. Its angled slits split starlight into a distinctive three-line diffraction pattern. When the telescope is perfectly focused, the central line sits exactly centered in the X formed by the other two — giving you an unambiguous, repeatable focus indication that is far more precise than judging sharpness by eye.
How do I use a Bahtinov mask?
Place the mask over your telescope's aperture, point at a moderately bright star, and look at the live view from your camera. Adjust the focuser until the central diffraction spike is centered in the X-pattern. When it's centered, you're in focus — typically under 90 seconds. Remove the mask before imaging.
Do I need a telescope-specific or an adjustable mask?
If you image with one telescope, a telescope-specific mask sized to that aperture gives the cleanest result and most secure fit. If you own several scopes or have a tube we don't make a dedicated size for, an Adjustable Bahtinov Mask covers a range of diameters with a single mask.
What's the difference between a Bahtinov and a Tri-Bahtinov mask?
A standard Bahtinov mask shows focus. A Tri-Bahtinov mask shows focus and collimation error simultaneously through a three-way spike pattern, which matters most for fast focal-ratio astrographs where small misalignments are visible in the stars.
How do I know which size to order?
Measure the outside diameter of your telescope's optical tube or dew shield and match it to the mask size, or use the Focus Mask Finder, which maps 191 telescope models to the correct mask. The mask does not need to be perfectly centered — the slit angles ensure accurate results regardless of positioning.
Note: Measure the outside diameter of your dew shield or OTA to select the correct mask size. The mask does not need to be perfectly centered — the slit angles ensure accurate results regardless of positioning.