|
fwiw) The club scope in Bunbury WA has (or had?) a 20" primary made from a slumped 3/4" pyrex (meniscus) blank. The lateral support was effected via a central plug. Whilst it is true that it did form an image of sorts, I cannot say that it was ever a satisfying instrument to use. My old 12.5" f6 with a Parkes mirror produces a more pleasing view on any (and every) night that they were operating from the same location. (and that is being polite)
~2c
|