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.
Make sure the mask is
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Precision Laser Cut PlexiglassThey 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. |
Come with Well Protected 3 ScrewsThe 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 190mm.
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 120mm.
