I'll be trying gout this mas next week
Knocked one of these over today for the C14,
6 mm foam board (with black cardboard on both surfaces), might spray it with something to plastify it? but then that might cause some ondulations...not sure. Anyways, worth a try i guess
Overall diameter 16 inch inside circle diameter 14"
slits of 12mm (same width for closed/open/straight and angled sections)
will let you know how I go
The two small tabs will be bent, the large one is for handling it and has a hole in it to hang up the mask when not in use
cheers
frank
PS thanks to everyone and Mr Pavel
Bahtinov for their contributions to the amateur astrophotography world!