3D Astro Bahtinov Focus Mask - 118mm ID
Stock count is accurate & shown in real time.
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
Contiguous US / Lower 48:
Free shipping applies to orders over $50 using our chosen carrier/method. Faster paid options are available at checkout.
Alaska, Hawaii & US Territories:
Free shipping applies to many—but not all—products. Enter your ZIP code in cart or upon checkout to confirm options and costs.
International:
International orders do not qualify for free shipping. Shipping, duties, brokerage, tariffs, and taxes are the customer’s responsibility. Some items may be restricted due to export, size, or manufacturer limitations.
Bahtinov mask to aid in focusing your Askar 40mm Guidescope # FMA180. Will also work for similar scopes which have a dewshield outside diameter of 52mm (check your guidescope before purchase if you are not sure).
We're not sure how necessary or effective this might be on a small-aperture guidescope, but several people have expressed interest in this item, so here it is.
With the mask on, you can see a diffraction spike pattern. Focus until you achieve a symetrical pattern. Once the best focus has been achieved, you can remove the mask and use the guide scope as normal.
This mask is deliberately designed to fit loosely over the guidescope dewshield so that it can be removed very easily when focusing is accomplished. It does not have a firm fit like an end cap would so that the imaging setup isn’t disturbed when you take this off.
3D printed from PLA.
Color of current stock is silver-gray but is subject to change without notice.
Other Information
- Country of Manufacture: United States
Bahtinov mask to aid in focusing your Askar 40mm Guidescope # FMA180. Will also work for similar scopes which have a dewshield outside diameter of 52mm (check your guidescope before purchase if you are not sure).
We're not sure how necessary or effective this might be on a small-aperture guidescope, but several people have expressed interest in this item, so here it is.
With the mask on, you can see a diffraction spike pattern. Focus until you achieve a symetrical pattern. Once the best focus has been achieved, you can remove the mask and use the guide scope as normal.
This mask is deliberately designed to fit loosely over the guidescope dewshield so that it can be removed very easily when focusing is accomplished. It does not have a firm fit like an end cap would so that the imaging setup isn’t disturbed when you take this off.
3D printed from PLA.
Color of current stock is silver-gray but is subject to change without notice.
Bahtinov mask to aid in focusing your Askar 40mm Guidescope # FMA180. Will also work for similar scopes which have a dewshield outside diameter of 52mm (check your guidescope before purchase if you are not sure).
We're not sure how necessary or effective this might be on a small-aperture guidescope, but several people have expressed interest in this item, so here it is.
With the mask on, you can see a diffraction spike pattern. Focus until you achieve a symetrical pattern. Once the best focus has been achieved, you can remove the mask and use the guide scope as normal.
This mask is deliberately designed to fit loosely over the guidescope dewshield so that it can be removed very easily when focusing is accomplished. It does not have a firm fit like an end cap would so that the imaging setup isn’t disturbed when you take this off.
3D printed from PLA.
Color of current stock is silver-gray but is subject to change without notice.
Other Information
- Country of Manufacture: United States
3D Astro Bahtinov Focus Mask - 118mm ID