Chuck, Yep, over the years my little RV-6 has stacked up very well against the competition, and has out-performed many larger scopes. And on the Dynascope list you often hear owners talk about how consistently good the optics were in the mirrors Criterion used. Brittle tubes, yes, undersized mounts, yes, but fantastic optical performance. And it sure is a lot easier to haul out than the 16-inch! Speaking of the 16 however, it does deliver wonderful planetary views with the longer focal length (f/6.25) and the small secondary (only 13% obstruction). I'm going to have to pursue Encke more rigorously when the weather cooperates. Just wish I had an equatorial platform to keep things centered at high powers... Rich --- Chuck Hards <chuckhards@yahoo.com> wrote:
Rich, I'm glad that you're into that Dynascope. Truth be told, I probably use my own 6" f/8 more than any other scope, even more than my 10". That clean f/8 with only a 1" obstruction produces the most contrasty, well-corrected image I've ever seen. The 5" doublet refractor can't hold a candle to it, even the 10" isn't as contrasty. People have told me that the image is as good or better than much larger instruments they've looked through. Now, statements like that do my ego a lot of good, but I think it's more a testimonial to how poorly-collimated the average telescope is. Also, the "sweet spot" of diffraction-limited performance is much larger on an f/8 than the f/4 & f/5 light-bucket Dobs. You don't need to keep the target in the exact center of the field for best resolution.
Any other 6" f/8 fans out there?
BTW, there is much good Saturn info. in the Observer's Handbook, although they don't mention Enke's minima in the edition I grabbed yesterday (2001) and I haven't picked up this year's yet (shame on me!)
C.
--- Richard Tenney <retenney@yahoo.com> wrote:
Chuck,
No, this was actually posted a day or two ago in the Criterion Dynascope group -- discussions of Saturn observing abound it seems.
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