Astromania Bahtinov Mask Focusing Mask for Telescopes - FM60mm for Tube Outer Diameter from 65mm-100mm

Astromania Bahtinov Mask Focusing Mask for Telescopes - FM60mm for a Tube Outer Diameter (OD) from 65mm-100mm - can be Mounted with The Brass Screws Inside or Outside The drawtube

Astromania Bahtinov Mask Focusing Mask for Telescopes - FM60mm for Tube Outer Diameter from 65mm-100mm

Visit the Store Visit the Store Visit the Store The Bahtinov mask has become the preferred method of focusing a telescope, either visually or when imaging with a CCD camera, DSLR or webcam. They are an inexpensive tool which will allow you to achieve pin-sharp levels of focus, saving you time and improving your work. Simply place the mask over the front of your scope, align the scope towards a star. The mask displays a unique diffraction profile, one part of the diffraction pattern moves in response to changes in focus and displays error as a displacement from a clearly defined point. Adjust the pegs so that each is at roughly the same position in its slot. To ensure a tight grip, loosen one thumbscrew slightly, then push the grip peg inward while pulling the mask gently toward the loosened grip peg. This will make sure that the other two grip pegs are contacting the telescope when you retighten the third thumbscrew. Now the mask should be well secured in position over the front of the telescope. You re ready to focus! They are made from precision laser cut enforced plexiglass, which is stiff and long lasting. They will never be brittle in the cold, unlike some other masks which are made from normal plastics. The masks grip the telescope tube gently but firmly with three metal posts which have non-scratching silicon sleeves to protect you valued telescope surface. Place the brass screw on the inside of the the dew tube. Slide each of the three grip pegs inward until they cling to inside of the telescope s front cell or dew shield, then tighten the thumbscrews. The maximum applicable telescope inner diameter is 110mm. Place the brass screw on the outside of the the dew tube. Slide each of the three grip pegs inward until they clamp outside of the telescope s front cell or dew shield, then tighten the thumbscrews. The minimum applicable telescope outer diameter is 60mm.

Key Features

• ✅ Bahtinov masks take the guesswork out of focusing and even get over the seeing conditions as it is a mathematical type approach to the task.The best focus for your telescope quickly and easily.
• ✅ Suitable for use on all types of telescope - reflectors, rafractors, Dobsonians, Mak-Cas and SCTs. They are made from precision laser cut enforced plexiglass, which is stiff and long lasting. They will never be brittle in the cold, unlike some other masks which are made from normal plastics.
• ✅ The masks grip the telescope tube gently but firmly with three metal posts which have non-scratching silicon sleeves to protect you valued telescope surface. This prevents slippage, whilst allowing the mask to remaining perfectly central. Because of this 3-post mounting, the mask remains centered, whilst fitting a wider range of telescopes.
• ✅ They are made from 2mm thick laser cut plexiglass and the securing screws are capped with soft plastic so that they do not damage your telescope.These high quality Bahtinov masks are adjustable to fit a wide range of optical tubes, unlike masks which are only able to fit one telescope. They have adjustment latitude of about 65-100mm, depending on model, in aperture making them very versatile.
• ✅ Please be assured that these focusing masks will work excellently for both reflectors and refractors with whatever focal length. All you need to do is to measure your telescope tube size and choose the right size of the mask (contact us if you are not sure where to measure).

✅ Product Dimensions: 5.12 x 5.12 x 0.12 inches

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