Bahtinov Focusing Mask Ritchey-Chrétien 25” or 11” Schmidt-Cassegrain or

25” or 11” Schmidt-Cassegrain or EdgeHD optical tube

but the background sky will be very dark as the contrast effect increases with added magnification

Description ED102mm FCD100 Series Carbon Fiber Air-Spaced Triplet Refractor Item Number FCD100-10207-CF Focal Length 714mm Focal Ratio f/7 Weight 7lb

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Bahtinov Focusing Mask Ritchey-Chrétien 25” or 11” Schmidt-Cassegrain orThe new Optical acrylic sheet offers 92% of light transmission that gave you the highest and brightest diffraction Spikes for Focusing about 3 times brighter than traditional bahtinov masks! Includes metal pegs to hang the mask over the front dew shield while focusing. Select the size appropriate for your telescope or lens. Model MM Inches BM DS GR45 75 110 2. 9 4. 3 BM DS GR55 105 148 4. 1 5. 8 BM DS GR90 172 235 6. 7 9. 2 BM DS GR150 243 308 9. 5