Just wandering, is it possible to c c machine and polish high grade stainless steel plate into a primary mirror?. ( 6mm to 10mm thick depending on size of mirror)
You would never have to re coat again.
Cleaning would be easier.
Attachments could be screwed straight on eg. Baffle tube.
Maksutov has made a 0.7m telescope
Check out link:
http://books.google.com.au/books?id=...mirror&f=false
Here is also another link, Note on page 29,30:
The thermal sensitivity of a metal mirror is lower than that of a borosilicate (BSC) glass one as metals have high thermal conductivities.
https://docs.google.com/viewer?a=v&q...zYB8BhSIe_df_Q
Den