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How to Choose the Right Bahtinov Mask for Your Telescope
How to Choose the Right Bahtinov Mask for Your Telescope
Focusing is one of the most critical steps, whether for visual observing or astrophotography. A Bahtinov mask makes this process both simpler and more reliable—but only if it’s properly matched to your instrument. In this guide, I’ll share some practical tips to help you choose the mask that fits your setup best.
Why choosing the right mask matters
Every instrument has its own characteristics: aperture, focal length, and especially the well-known f-ratio (F/D). These parameters directly influence the diffraction pattern produced by the mask. In other words, a “one-size-fits-all” model rarely works perfectly.
That’s why I only produce custom-made masks, designed specifically for each instrument. The result: cleaner diffraction spikes and a focus that’s both quicker and more accurate.
That’s why I only produce custom-made masks, designed specifically for each instrument. The result: cleaner diffraction spikes and a focus that’s both quicker and more accurate.
Practical examples by instrument type
- Newtonians: a 150/750 Newtonian won’t use the same mask as a 200/1000. Both aperture and f-ratio are decisive in shaping the slit geometry.
- APO/ED refractors: for instance, the Askar FRA400 and FRA500 have similar apertures but different f-ratios, so their masks must be calculated separately.
- Ritchey-Chrétien (RC): with their long focal length and sensitivity to collimation, RC8" or RC10" telescopes benefit most from Tri-Bahtinov masks, which assist with both focusing and collimation.
- Camera lenses (Samyang 135mm f/2, Canon, Nikon...): each lens requires precise calculation depending on focal length and aperture. A Samyang 135 f/2 won’t use the same mask as an 85mm f/1.4.
- Schmidt-Cassegrain (SCT) & Maksutov: these closed-tube instruments also benefit greatly from Tri-Bahtinov masks, since they allow fine-tuning of both focus and optical alignment.
⚙️ Why I only make custom masks
- ✅ A properly calculated mask produces a diffraction pattern that’s easy to read.
- ✅ No compromises compared to generic “adaptable” models.
- ✅ Accurate results from the very first star—no guesswork.
- ✅ Each mask is individually crafted in my workshop, with a visual check after every print.
Craftsmanship meets precision 3D printing
All my masks are 3D-printed in my workshop using high-quality PETG filament made in Europe. Each model is dimensioned to fit your dew shield precisely, with a slight oversize to allow a felt strip inside. This felt prevents scratches on your instrument and ensures the mask stays firmly in place while focusing.
Need advice before ordering?
If you’re unsure which mask best fits your instrument, feel free to contact me. I’ll confirm the dimensions and parameters of your telescope, refractor, or lens before making the mask.
Each mask is made with the same attention to detail and passion for amateur astronomy. That’s what ensures fast, reliable focusing—night after night.
Examples of Bahtinov masks available in the shop:
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Bahtinov Masks Explained: How to Master Sharp Focus
What is a Bahtinov mask? How do you use it? And what’s the difference between a Bahtinov and a Tri-Bahtinov? Let’s...Voir plus
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