Image of the day

Captured by
Philip Imbrogno

M 33

About Astromart

My Account

New to Astromart?

Register an account...

Need Help?

Questar Mirror Composition

Started by Sailcat, 05/08/2003 03:31AM
Post Reply
Posted 05/08/2003 03:31AM Opening Post
Walter Locke
View public profile Send a private message to Walter Locke Find more posts by Walter Locke Find threads started by Walter Locke
Forum Member
Sailcat's avatar

Join Date: May 2002

Location: Ione CA, US

Posts: 104

Questar used to offer Cervit mirrors as an option on its scopes. I believe Questar now uses Astrosital as the premium option. Why the change, and are those vintage Questars with cervit mirrors at a disadvantage somehow?

Thanks,

Walter
Quote
Walter Locke
"The Fearless Spectator"

There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.
Richard Feynman
US educator & physicist (1918 - 1988)



Posted 05/09/2003 02:35AM #1
Walter Locke
View public profile Send a private message to Walter Locke Find more posts by Walter Locke Find threads started by Walter Locke
Forum Member
Sailcat's avatar

Join Date: May 2002

Location: Ione CA, US

Posts: 104

Thanks Herbert. Some time ago I spoke to an optician who explained that many of these ceramic mirrors might not rebound to their original shapes after heating and cooling a certain number of times. These changes would be small but cumulative over the life of the mirror. This makes the ceramic mirrors in those otherwise beautiful Questar telescopes a bit suspect, alas. Thank goodness for Pyrex!

Walter

Quote
Walter Locke
"The Fearless Spectator"

There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.
Richard Feynman
US educator & physicist (1918 - 1988)



Post Reply

Funding Member

Sponsors


View all sponsors

Search