Quote:@Stipe, Yes, the synta is under-corrected. I have been playing around with the spacing, range is from .005 to .015. I want to see if it changed the image at all.So what I do is leave the spacers in place and add oil. I guess I could use some good tape on the outside of the objective so the oil doesn't leak out.What kind of oil to use? What would be the spacing of the objective when using oil? Can or should I leave the spacers in place when using the oil? Like I said, my spacing would be at low end .005.Paul
Quote:The shift to a C-e achromat was discussed some time ago by Roland Christen (link). It indeed is a better planetary scope shifting red and green to a common focus, where most planetary detail information is contained, and allowing the blue to go further out of focus. Therein is the problem. While this correction gives good planetary views, the stellar capability has been degraded. This type of correction will not be a good all-around scope, but would indeed be a very good planetary scope. Have you specifically observed some blue, blue-white stars with this scope since the oil-spacing? You may be disappointed.
In fact, I approached RF Royce Optical about making a custom C-e oilspaced achromat specialized for planetary for me. Robert asked why would I want such a thing? I told him that Roland had confirmed that it would be a great planetary scope but, Robert said it would be good at nothing else. He refused to make it, saying he would only stick with the C-F design which he does oilspace. He said everything else in the universe beyond the planets needs the blue end and making a scope solely for a handful of objects wasn't cost effective for the slight benefit.
Link to C-e Discussion
Quote:Anyother concern is when I tighten down the objective in the cell. Would this not squeeze out the oil between the two lenses?Paul
More Telescopes than I deserve...
Keeper of the Swamp Gas Observatory "This R2 unit has a bad motivator" AR127, CG4 CGE1100 1984 tasco 60mm 49TR F/13.3 refractor 1976 Vixen Polaris 80mm F/15 refractor Denkmeier Big Easy BV'er Astro-Tech Titan 38mm 70* Astro-Tech Titan 20mm 70* Astro-Tech SR6 12mm 60* Meade MA25mm Jap. Meade MA9mm Jap. TMBpII 5mm ES 1.25" FX
Quote:Okay, first I used mineral oil with no spacers. It looked like the glass was touching its self. Gave a ring like glare through the glass. I was worried so I used a .004 spacer. Well, by trying to separate the glass by sliding it away from each other. I got some very fine scratches on the glass.Is there a way to clean up the glass ?Anyway, I did a look through the scope with the spacers, had nothing to loose now. It basically reversed the in and out of focuse rings. Before it was under-corrected it is now over-corrected.Other issue was the oil started to drain out because of the .004 space. So, with fine line scratches in the glass, I will try with no spacers next time.My concern, like I said, is the glass making contact with its self because it is not perfectly matched.Paul
Quote:It's fine scratches, no doubt it sad to say.Now what about if the glass is going to make contact with its self. When I first used no spaces, I noticed rings in one area of the glass. With the .004 spacers in place no such rings appear. Now, is it actually making contact or is it the space is so close it will make those rings. Will it affect the optics if I go ahead and use no spacers and the oil?What shall I do?Paul
Leica 8x20; Nikon 7x35; Vixen 8x42; Orion 15x63; Docter 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet