William Optics Diffraction Spikes Bahtinov Focusing Mask - Dew Shield 243 mm to 308 mm - BM-DS-GR150 Free Shipping the included slow motion controls

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

16") Back focus from top of threaded collar 77

whether 2 inches or 2 feet

15° Useable field 32 mm (1

William Optics Diffraction Spikes Bahtinov Focusing Mask - Dew Shield 243 mm to 308 mm - BM-DS-GR150 Free Shipping the included slow motion controlsWilliam 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