-Brian 14" Hubble Optics ATM Newtonian Paracorr II Ethos Eyepieces VE9WTH
-DannyMy warehouseMy Channel
Ex Oriente, astrum ---------------------- From the day you are born 'til you ride in a hearse, There's nothing so bad that it couldn't be worse!
8" Criterion Dynamax 6" Homebuilt F/10 Newt 6" F/8 Jaegers 127mm F/5.5 SS Assembly Various 60 mm scopes in many states of repair 8' Dome Observitory
Quote:So here it goes………………I have an inexpensive 2” rack & pinion focuser to use initially for testing. I have been looking at 0.75 – 1.00 inch secondary’s from Protostar. A friend is offering to let me use a couple of his spare secondary mirrors for testing.
Quote: I know a 0.75” secondary is a little small if I wanted to observe wider field of views. However, my friend’s scope, with a 0.75” secondary, produced amazing images at “moderate to high” magnifications. I did not observe any fall off of image brightness.
ATM Nut.6" F15 Jaegers Refractor on Homebuilt EQ mount12.5" Homebuilt NewtProjects:16" F7.2 Reflector
Quote: Here is a link to an old thread in the Archives which will tell you everything you want to know. It's long, but a great read! Reflector vs Refractor?
Quote:Here is a focuser idea for you--Use a KineOptics HC-1 mounted on a metal plate inside the tube. This will allow placement of the focal plane 1" or less above the outer tube surface. With a secondary to focal plane distance of 6" you can use a 0.75" diagonal!
Jeff Morgan - Wile E. Coyote School of Telescope Making
Quote: Transportability might not be as bad you think. For my 10" f/9 I used a Yakima kayak roof rack
Quote: Quote: Transportability might not be as bad you think. For my 10" f/9 I used a Yakima kayak roof rack With a 90 inch focal length, it must have required a substantial stool or probably a ladder. How did you carry that?Jon
__________________________________________________________________________________________________________________Sheet Metal Worker/Welder Indiana Astronomical Society 6" f/10 home brew dob, Quantum 4, 90mm Apex Mak, Criterion RV-6, Criterion RV-8, Coulter Odyssey 1 13.1", Meade 16" Lightbridge, Sears Discoverer 4-6305A, Manon 60mm (The Marsha Scope), Towa 11T, Tasco 10TE
Pentax XL 10.5mm, 14mm
Meade 5000 SWA 34mm, 28mm, 24mm, 20mm
Televue Plossls 21mm, 17mm,
Televue Nagler T1 7mm
Orion Ultrascopic 30mm
Celestron Ultima 18mm
U.O. Orthoscopic HD6mm, HD9mm, HD12mm
Televue 2x Barlow
U.O. Klee 2.8x Barlow
Lumicon OIII, Baader Contrast Booster, DGM NPB 2 inch, Celestron OIII 2 inch
Pentax 10x50 WPII Binos
Celestron Nexstar 40mm
Orion Sirius Plossl 32mm
Meade 5000 Plossl 20mm
Celestron 2x Barlow
Quote:IMHO, (and I am certainly no expert and I don't even have good skies for critical observing), you are putting a huge amount of energy into trying to fix a problem that doesn't really exist. The secondary size is not going to affect your image in any way that you will be able to observe in the eyepiece.
"The White Zone is for loading or unloading of passengers only. No Astrophotography." Cosmic Acres! Greatest restoration challenge: Tulley and Sons 3" achromat on Altazimuth mount, circa ~late 1820s
Quote:I don't know about all y'all's preferences, but I do have to say that nothing would have me pulling my hair out in large tufts more than a long focus planet-killer on a non-driven mount! You could build a platform for a dob, of course, but one to support an 8"f/10 would likely be LESS compact and transportable than a good old-fashioned GEM. Back to your regularly scheduled program, which is already in progress.... Tim
Quote:Lots of good info here: http://stellafane.org/tm/dob/index.html