Classic refractors incl. Unitrons, Zeiss, Goto Optical, Royal Astro, Edmund; visual observer.
"Toto, I have a feeling we're not in Kansas anymore!"
Quote:Any relay lenses in the baffle tube?Dave
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics Engineering = Taking what you have and making what you need.
Quote:The finder is an old Edmund unit. I have one. It was made with a WWII "Erfle" eyepiece.
Quote: As for the optical design of the telescope, it is most likely either a folded Newtonian or a Maksutov. In a Mak the corrector can have shallow curves when it is used with a slow primary. - Dave
Astronomy educator/Sidewalk astronomer
Owner of Astronomy Delight franchise
18 inch f4.42 Dob on eq platform w ST120 f/5 finder
12 inch Zhumell Dob
8 inch f/6.9 home made Dob with Seevers optics
William Optics red 10th Anniversary 80mm FD
C8 XLT on Vixen GPDX
26lb eyepiece box
Cernan Space Center astronomer
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Quote:The back of this scope looks exactly like my Meade 8 inch Starfinder I used to own. I even drilled the 3 holes exactly like the ones shown here. Interesting.
Quote: Since you have the mirror out of the OTA, I would bench test it. In a few minutes you'll know if it's something close to a parabola or spherical.
Quote: If spherical then the front glass would need to be a menicus for the system to have a chance of working. If it looks like the mirror is parabolic then the front glass needs to be a high quality optical window.
Quote: You also know if the usual diffraction pattern is coming from the mirror or the corrector. If it coming from the mirror then you can take it out the cell and see if it goes away.
Quote: I've seen a couple of homemade "telescopes" made from military optical parts that don't belong together and just won't work. This has that look about it.
Quote: My guess is that the mirror might be Ok but the window/corrector is not a precision piece of optics. - Dave
Quote:Quote:The back of this scope looks exactly like my Meade 8 inch Starfinder I used to own. I even drilled the 3 holes exactly like the ones shown here. Interesting.
Interesting.. With the particle board and sonotube construction, it definitely screams 1980's construction techniques.
Quote: If the ronchi lines show a fair amount of curvature then the mirror is not parabolic but hyberbolic or an oblate spheroid and maybe strongly so. A 6" f/8 parabola would show only slightly curving Ronchi lines and if one wasn't careful could mistake them for straight. You said that the lines were convex in curvature. Were you inside or outside of focus when they showed this pattern since this would determine if the mirror was an oblated spheroid vs a ellipse/parabola or hyberbola ?
If the other 6" mirror looks to be a sphere you can use it to test the corrector by placing it in front of the mirror while your testing the mirror. If it is an optical window with no optical power the ronchi lines will stay unchanged.