William Optics Diffraction Spikes Bahtinov Focusing Mask - Dew Shield 243 mm to 308 mm - BM-DS-GR150 Free Shipping Optical test report

Optical test report

Astronomers quickly learn that viewing the Moon with a telescope (but without any Moon filter) is just too bright for most person's eyes

the included slow motion controls make it easy to have smooth tracking to follow objects in the sky as they move

up-close views of small subjects when needed

William Optics Diffraction Spikes Bahtinov Focusing Mask - Dew Shield 243 mm to 308 mm - BM-DS-GR150 Free Shipping Optical test reportWilliam Optics Diffraction Spikes Bahtinov Focusing Mask For Dew Shield 243 mm to 308 mm William Optics Diffraction Spikes Bahtinov Focusing Mask Fits dew shields with diameters of 243 mm to 308 mm Clear Acrylic Sheet design provides 92% light transmission Gives the Brightest diffraction spikes for focusing This is a William Optics Diffraction Spikes Bahtinov Focusing Mask made from Acrylic material, which is high in light transmission. This design