Binorum Bahtinov Focusing Mask 230-290 mm
A sharp image starts with precise focus - and that is exactly what a Bahtinov mask delivers. This plastic focusing mask for astrophotography fits over the front of any telescope with an outer objective diameter of 230 to 290 mm. Its grid pattern lets you achieve a level of focus accuracy that the naked eye and standard focuser adjustment simply cannot match.
How it works
The process is straightforward and anyone who photographs through a telescope can use it.
- Place the mask over the front of your telescope.
- Point the telescope at a bright star.
- Switch your camera to live view mode and observe the star on the screen.
- If focus is off, the central spike of the Bahtinov diffraction pattern appears shifted relative to the two outer spikes.
- Slowly adjust the focuser until the central spike sits exactly between the two outer spikes.
- At that point, your telescope is perfectly focused for astrophotography. Remove the mask and begin your exposure.
No power, no complex setup
The mask works on a purely optical principle. It requires no batteries and no configuration. The result is visible immediately on your camera display.
About Binorum
Binorum is a brand built by astronomers for astronomers. Every product focuses on quality construction and practical usability - without unnecessary compromise. Binorum offers a wide range of astronomical accessories, so you can find most of what you need for observing or imaging in one place. The philosophy is simple: equipment should serve the observer, not cause extra trouble.
Technical specifications
| Parameter |
Value |
| Compatible objective outer diameter |
230-290 mm |
| Material |
Plastic |
| Power required |
None |
| Focuser connection type |
Slip-on (friction fit) |
| Application |
Astrophotography focusing |
| Brand |
Binorum |
