Achieve perfect focus and collimation with this custom 3D printed Tri-Bahtinov mask designed specifically for Schmidt-Cassegrain telescopes. If you would like a different size, please let me know and I can add what you need. The Tri-Bahtinov mask is very similar to a regular mask, except the diffraction pattern produced 3 times, 120 degrees apart. This allows for fine focus control, as well as collimation by making sure your scope is in focus in all directions.

The optional isolator mask allows for easier collimation by only allowing one pattern to appear at a time

For sizes over 9.25 inch, or for telescopes fitted with Hyperstar, the mask will come in 3 parts that snap together with magnets. My products are 3D printed to order by me, and as a full time physics student I am often quite busy, so some items may be a little delayed depending on my schedule, most items are dispatched in 1-5 days. The 3d printed items can be a bit delicate depending on the design, so need to be treated with care, and can occasionally very minor imperfections may be noticeable, but will not affect the item in any way. If you have any problems with an item once it arrives please let me know. Shipping: UK Items are shipped Royal Mail 24, tracking will be provided and items should arrive within maximum 7 days from ordering, if item has not arrived by this time, please let me know. Europe Standard items are shipped with Royal Mail International Standard delivery which Royal Mail claims to arrive in 3-7 days however I find this usually takes between 1-3 weeks and has no tracking. Express delivery with tracking (usually with dpd) can be selected if desired. Rest of world Standard items are shipped with Royal Mail International Standard delivery which Royal Mail claims to arrive in 3-7 days however I find this usually takes between 1-4 weeks and has no tracking. Express delivery with tracking (usually with dpd or dhl express) can be selected if desired.