· Get a Cloudy Nights T-Shirt · Submit a Review / Article    Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Forum Archives · Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Equipment Discussions >> ATM, Optics and DIY Forum Previous   Index   Next   Threaded   Pages: 1 Ian Robinson Pooh-Bah Reged: 01/29/09 Posts: 1165 Loc: Gateshead.NSW Nth Coast,Austra... Aluminium tubed newtonians       #3384908 - 10/12/09 07:56 AM Edit   Reply   Quote Quick Reply   If you have used aluminium sheet rolled to a "big" tube .... for a newtonian (ie bigger than 6" which I think is as big as you can buy as a extruded aluminium tube) What were your tube dimensions (Length, diameter and aluminium sheet thickness) ? Are you happy with it's strength , stiffness and ability to hold collimation ? Post Extras:       Bird Post Laureate Reged: 08/07/03 Posts: 3025 Loc: Canberra, Australia Re: Aluminium tubed newtonians [Re: Ian Robinson]       #3386582 - 10/13/09 03:48 AM Edit   Reply   Quote Quick Reply   Ian, I have 3 of them - a 12" tube for a 10" mirror, a 15" tube for a 13.1" mirror and most recently a 20" tube for a 16" mirror. All rolled from thin aluminium - 0.9mm thickness - and with internal steel strengthening rings to give extra support. Also the top and bottom ends of the tubes have extra strengthening rings as well. There's been no problem with any of these in tube flexure, although I have had some mirror and mirror cell flop that was a problem in the earlier versions, but that's fixed in the latest version (the 20" tube) with a much stronger mirror cell than before, so now the scope holds collimation right across it's range of motion. cheers, Bird -------------------- Deep Sky Optics 13.1" f/5.5 newtonian, PGR Dragonfly Express, PGR Dragonfly 2 RedHat Linux + Coriander http://www.acquerra.com.au/astro/ Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 17 registered and 6 anonymous users are browsing this forum. Moderator:  Don W, Mike I. Jones  Print Thread Forum Permissions       You cannot start new topics       You cannot reply to topics       HTML is disabled       UBBCode is enabled Thread views: 234 Jump to *International Year of Astronomy 2009* -----   Global Coordination   Cornerstone Projects   Special Projects   Special Task Groups   Global Activities   National and Regional Activities   IYA 2009 in Africa   IYA 2009 in the USA*Announcements and News* -----   Cloudy Nights Announcements   Discussion of CN Articles, Reviews, and Reports   Beginners Forum   Celestial Events   Light Pollution*Equipment Discussions* -----   ATM, Optics and DIY Forum   Binoculars   Binoviewers   Cats & Casses   Classic Telescopes   Equipment   Eyepieces   Mounts   Observatories   Reflectors   Refractors    Celestron SkyScout and Meade mySky   Video and Electronically Assisted Astronomy*Astrophotography and Sketching* -----   Beginning and Intermediate Imaging   Film Astrophotography   DSLR & Digital Camera Astro Imaging & Processing   CCD Imaging & Processing   Solar System Imaging & Processing   Sketching   Astro Imaging/Sketching Contest *Observing* -----   NEO   General Observing   Planetary and Solar System Observing   Lunar Observing   Deep Sky Observing   Double Star Observing   Solar   Variable Star Observing and Radio Astronomy*Telescope Specific Forums* -----   Celestron NexStar    NexStar GPS / CPC Telescopes   Questar Forum   Meade ACF/RCX / LX / GPS    Meade ETX*Other* -----   Science of Astronomy & Space Exploration   AstroWebsites   Space Rocks*Speciality Forums* -----   AstroArt   Astronomy Software & Computers   Stellar Media   Astro Outreach, Clubs and Star Parties*CN Feedback and Vendor Announcements* -----   Vendor and Group Announcements CN Forums Home

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