Quote:Few years ago was the start of the last project, a pair of 40” instrument. The goal was to make to identical dob structure, one for the optician and one for me. So I made two structure.
A 60mm department store refractor started it all....
Jc ATM 10" F6.1, 1/25th wave spec (max wavefront error +/- 1/12.6 in zone 4 of 6, sodium light ), 6" F7 spec, 127mm F9.4 achro Refractor, Criterion DX8, 10 x 50 bin, SP mount/Synscan goto. ETX80 (finder) Canon 20D, PST DSI 1, Butenschön 125mm F13.4 refractor, diy spectroscope and curiosity
Chris Cape Town
Nytecam 51N 0.1W Meade 30cm LX200 astrograph+C8+Ha+CaK PSTs+spectrographs SX M9+Lodestar-C+M CCDs/Canon 1100D DSLR My Meade astrograph-colour deepsky My supernova discovery My dome build/spectroscopes/DSO images/Lodestar colour images & videos
Quote:A 40" next to a 24 I made years ago.
It was a 20x power, 0.3° field of view telescope, sporting a singlet objective stopped down to 15 mm that profoundly changed our perspective on earth's place in the universe.
I mostly enjoy small, fast, and (ultra)portable glass: Bushnell Legend 8x42, Pentax PCF WP II 20x60, MiniBorg 60ED, ST-80, EON-80, ST-120, 6" StarBlast.
22" and 14" Dobs on EQ platforms and Deep Sky Observing
Focus on Astronomy Outreach Project www.focusonastronomy.org Sky-Watcher USA Product Specialist email@example.com
Quote:Naah, he needs to get hooked up with those guys in Oklahoma with a 61" mirror and telescope project!
Scopes: 8" f5.75 OOUK newt (.977 strehl, curved spider) on a hypertuned Meade LXD75. Meade 6N newt OTA; Celestron Onyx 80mm f6.2 ED semi apo on SW AZ3; IKI 70mm ED apo on Vixen Porta Mini mount; Ha PST on photo tripod; 10x50, 15x70, 20x80 binos; (wishing for Sumerian Optics 12" travel dob..) EPs: Meade 5000 SWA: 16,24,34; Meade 5000 UWA: 18,24 ; Baader Hyperion 8-24 Zoom mkII with 2.25x Barlow; Various Ploessl; WO Binoviewer; TV 2x Barlow Other:UHC, OIII, 600D with Magic Lantern.
Quote:That 40" is incredible. Jealousy is not something that I feel often, but 40" in a carbon fiber structure...
Celestron 8SE Dobstuff 13.1": Swayze refigured Coulter mirror, 6 pt mirror cell (2 pt edge support) and CF focuser board made by me StarBlast 4.5 ST80/PortaMount II Zhumell 20x80/Oberwerk 15x70 on a Seronik-style tripod boom mount Hubble Optics 18 inch F/4 mirror.
Quote:Amazing scopes!Quote:That 40" is incredible. Jealousy is not something that I feel often, but 40" in a carbon fiber structure...Prefabricated carbon fiber parts are incredibly expensive (a 10' long 1" tube at Aircraft Spruce is around $400) - but the carbon fiber fabric is much cheaper.The best fabric for a pole for maximum stiffness is probably unidirectional fabric.Instead of trying to make a 100% carbon fiber pole I am planning to experiment with reinforcing an aluminum pole by wrapping a carbon fiber/epoxy lay-up around the pole.Wrapping a 12 inch width (plus a bit more) of 9.0 oz./sq yard unidirectional fabric around a 1.5 inch wide, 0.058 inch wall pole will increase its stiffness by 150% (a 2.5 multiplier). This material costs $3.09 per foot at Soller Composites (http://www.solarcomposites.com/composites/carbon%20fiber%20uni-fabric.html) In quantities of 25-49 feet ($2.69 over 50 feet); more than an order of magnitude cheaper than the carbon fiber tubing. If you need 6 five foot poles the material cost is about $100, Not as light as pure carbon, but far better than pure aluminum. You could drop the aluminum thickness to only 0.035 inches for an even lighter composite pole.
Quote:About carbon on alu, it's better to add a layer of glass fabric between the two. I got some carbon part directly in an aluminum part on and old scope and the alu seems to slowly convert into a white powder