Polish high grade stainless steel plate into a primary mirror? Yes it has been done.

[Den]

:question: 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=zLvQYy41Ma4C&pg=PA219&lpg=PA219&dq=stainless+steel+telescope+mirror&source=bl&ots=rG86inKlBE&sig=-t-TLPRmit9FRJCJnr-YGEz1Y1o&hl=en&sa=X&ei=qyIzUfmwDMzTmAW6-4DICQ&ved=0CC0Q6AEwAA#v=onepage&q=stainless%20steel%20telescope%20m irror&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=cache:0IZj61AaN3cJ:www.springer.c om/cda/content/document/cda_downloaddocument/9780387887906-c2.pdf?SGWID%3D0-0-45-737915-p173851953+stainless+steel+telescop e+mirror&hl=en&gl=au&pid=bl&srcid=ADGEESiPHStcrsXZm7FIsOZIn_jLy gee3r652wpDBXqjdifwwbNaJtt2n0qpZXsi YlAr8pxbKRjc5Hl3mXmUAuGLb6Pyl6YZXuX H0HuPo2VJIfjmOgPQRD8X7x00cNxBHpTCCF dBYnis&sig=AHIEtbQk9SI1Vb8pZ4Y6zYB8BhSIe_d f_Q

Den

[dannat]

They use to make mirror out of speculum (Cu+Sn) so why not, reflect acne would not be nearly as good as a coated mirror I would think though
How would you shape it?

[bojan]

No!
Stainless steel is not thermally stable enough.

Guys, give up - NOTHING beats glass as a material for astronomical mirrors (only ceramics.. fused silica... but price!!!).

End of story.

[Den]

Mabe:
Computer controlled lathe, then polish after.
Or casting in to shape, then polish.

Allowance for polishing tolerances need to be calculated.

Den

[Den]

How about using a heating pad on rear of mirror.
Den

[bojan]

I know I might sound defensive now... but if those alternatives are any good, they would have been used already.

Glass rules! As simple as that.
Price-wise, performance-wise..