Hi all, thought I would let you know how the 18" of the 19" turned out. Had a problem star testing using Antares, as there seemed to be an optical defect that looked like a little blue star next to it. Turned out it was the Antares partner. I had no idea it was a double!
As for the silvering, it is a bit thin as I can just see through it so probably about 5nm thick, I think you need about 100nm to get a complete film.
On another subject there were terrible star test images showing triangular shaped star rings. This was caused by a wooden curved support for the lower part of the mirror. This has been replaced with a packing tape band to support the mirror and now stars are tack sharp, and Saturn looks like Raymond's pic. (Congrats Raymond, good effort). BTW I found a diag at Bintel suitable for f4.7, so allis well.
