Orion ED80; Coronado PST
Tasco 12TE 60/700, c. 1959; Tasco 66TE 50/600, c. 1978
114mm f/4.4 Newtonian half-Dob
Zhumell 25x100, Celestron 8x56
Manfrotto 028B tripod, 502HD head
Sirui T-2005X tripod, Giottos monopod, Manfrotto 222 head
Classic refractors incl. Unitrons, Zeiss, Goto Optical, Royal Astro, Edmund; visual observer.
"Toto, I have a feeling we're not in Kansas anymore!"
Quote:...the optical path for your new configuration of diagonal and 1.25 inch e.p.s is several inches longer that that of the original configuration. You will now need more in-focus than you have given the length of the tube. The alternative is to shorten the tube.
Astro-Physics 5" f6 ca.1986
The Jordan Levinson Refractor 4" f15 ca.60s or 70s (work in progress)
Orion Apex 102 102mm f12.7 ca.2013
Tasco 10TE 76mm f15.7 ca.1965
Tasco 7TE-5 60mm f16.7 ca.1967 "Focus on far-out stars with professional ease." -Tasco catalog
Tasco 66TE-5 50mm f12 ca.1966-1972, Tower 6314 50mm f12 ca.?
Quote:Your options as I see it are (1) shorten the tube (the main tube).(2) shorten the focuser drawtube (but then you have to rethread it. (3) move the objective cell closer to the back, (but again, that is going to require cutting and either re-drilling or re threading the main tube depending on how the cell is attached.
Yes, I too have telescopes and all of them are Go-To. Wherever I push them, that's where they Go-To. "When you earnestly believe you can compensate for a lack of skill by doubling your efforts, there's no end to what you can't accomplish"
Old brass and old glass
1st Caveman Award!Maynard Clark 8" f/8The Horsetrail Cave 12.5" f/7.51975 Cave 8" f/7 Lightweight Deluxe1972 Cave 8" f/4.5 RFT DeluxeCriterion RV-6Logitech HD C615 Webcam for Imaging
Quote: I see that Agena Astro has a GSO hybrid prism diagonal:http://agenaastro.com/gso-0-965-1-25-90-hybrid-erect-image-prism-diagonal.html
Quote:Try a prism diagonal as opposed to a mirror version. They have different light paths and focus travel can be an inch or so different. Chris
Quote:I'm now seeing two possibilities:1) .965 focuser - Tasco .965 diagonal - .965 to 1.25 adapter - 1.25 ep2) .965 focuser - .965 to 1.25 adapter - 1.25 prism diagonal - 1.25 ep
When the past no longer illuminates the future, the spirit walks in darkness. -- Alexis de Tocqueville
Quote:...bring your scope to a local telescope shop and try different diagonals (new + used)
Orange Tube C8, Tasco 7te-5, 4" Criterion Dynascope, Jason/Towa 313
Nikon Action Extreme & Pentax WPii Binoculars
At my club, everything one could want up to 18"
Antares 12" Dob Stellarvue 10*60 finder Telrad Meade 25mm Plossl, Orion 10mm plossl, Celestron 6mm plossl, Paradigm 18mm,15mm,12mm, 8mm, Knight Owl 20mm, Shorty 2x barlow, Celeston Ultima 2x Catseye Triple Pack Collimation 4.5" Tasco 11TR Frankenscope 60mm Tasco 9TE-5 60mm Tasco 7T Oberwerk 12*60 binos
Steve Verba 76mm Tasco 10TE 180mm Astro-Physics StarFire 20in. Obsession 15 x 15 Rolloff (Backyard Observatories)
4.5" f/10 A Jaegers Homebuilt Refractor,12"GSO f/5.3"Reflector,10"Meade LX-50 SCT, 8" Hardin f/6 reflector Yulin 5"f/9 refractor, 4.5"TASCOS Luminova,11TE-5 & 11TR Lunagrosso reflectors,Cel.100mm Reflector.3" Tasco 3TER 700mm 76mm reflector, Tasco 10TE 76mm 1200mm f/l Refractor 60mm TASCO 7TE-5 1000mm f/16.7 Refractor 60mm TASCO 9TE 700mm f/l refractor 60mm TASCO 9TE-0 710mm f/l Refractor www.vega-sky-center.com
Quote:How much focuser travel do you have?
Quote:I'll experiment with it over the next few days and see what I come up with.
Quote:I can't see there being so much of a difference in where the 12mm and 20mm eyepieces reach focus. Do they both have all their elements? I wonder if you had an adapter, what would result by trying them in one of your other scopes.
Clear Skies, Forever! The Vega Sky Center
254mm F/5.65 Homebuilt Fork Mounted Newtonian Reflector
152mm F/10 Jaegers Homebuilt ACHRO Refractor
152mm F/15 Fecker "Prototype" Homebuilt APO Refractor (to be constructed)
130mm F/9 LZOS Homebuilt APO Refractor (to be constructed)
127mm F/9.4 SS Homebuilt ACHRO Refractor
114mm F/8 Tasco 11te-5 Newtonian (to be restored)
102mm F/9 Meade 102ED Semi-APO Refractor
100mm F/13 Carton Homebuilt ACHRO Refractor
76mm F/15.7 Sears Discoverer 6339-A ACHRO Refractor
60mm F/16.7 Tasco 7te-5 ACHRO Refractor
60mm F/15 Jason Discoverer 313 ACHRO Refractor
Quote:Hi Eric,Terra did an awesome job of conveying you major issues, along with viable solutions. But, to add to what she and everyone else has suggested, I would try changing the visual back (the screw-on holder at the end of the draw-tube) to a short one. The one that you currently have is about 3/4 of an inch longer than the typical old-school design. If I find one among the collection of spare telescope components I have, I will be more than happy to give it to you in hopes that it will solve your dilemma. Sounds as if you only need a pinch more of in-focus.Mel