Support Astromart! | Log In | Help
Astronomy NewsTelescope ClassifiedsTelescope AuctionsTelescope Articles & ArticlesTelescope Articles & ReviewsTelescope and Astronomy ForumsAstronomy Events Calendar

View Forums
Start A New Thread
Display Preferences
Search Forums

User Name:


Save Login
New to Astromart?
Register an account...

Terms of Service
Privacy Policy
Help & FAQ
Astronomy Links
User Profiles
Top Users List
RSS Feeds

880 most users online in the last day
710 new forum posts in the last month
More site stats...

Home > Forums > ASTRONOMY > Beginning Astronomy? > Message #836514

Re: barlow basics

Posted by Chris Kelly on 11/11/2017 8:19 AM in response to Re: barlow basics   (92 hits)
 Prev Post Next Post 

Yes and yes , thanks. I picked up an Orion 2x shorty that works fine. M31 still looks the same. I need more photons in the tube. Or a bigger tube. Thanks for the wealth of info, I think I'm off to my next question.......
Why is glass or pyrex the chosen material for mirrors. It seems to me metal will be a lot easier and cheaper to remove minor spherical caps from flats within nanometer precision. Or a porcelain cast from the blank. ?..... Mirror treatment is all the same..... I am tempted to run a 4"x24" AlMg ingot thru my C&C machine then polish it up. Send it out for treatment. Done 23" mirror ?... Is there a reason why grinding glass is preferred, sounds exhausting.


Subject Posted By Date/Time Hits 
barlow basics Chris Kelly 10/28/2017 5:52 AM 137
Re: barlow basics Ed Blankenship 11/1/2017 9:04 PM 112
Re: barlow basics Ed Blankenship 11/1/2017 9:31 PM 82
Re: barlow basics Chris Kelly 11/2/2017 9:57 AM 99
Re: barlow basics Ed Blankenship 11/5/2017 3:51 PM 87
Re: barlow basics Ed Blankenship 11/5/2017 3:58 PM 99
Re: barlow basics Ed Blankenship 11/5/2017 4:31 PM 89
Re: barlow basics Chris Kelly 11/11/2017 8:19 AM 92
Re: barlow basics Thomas Dey 11/11/2017 4:45 PM 98
Re: barlow basics Chris Kelly 11/13/2017 6:44 AM 74

All times are in (GMT-8:00) Pacific Standard Time Zone  
Astronomy News | Telecope Classifieds | Telescope Auctions | Telescope Reviews | Telescopes | Telescope and Astronomy Forums | My Account | Help | RSS