Thanks, Chuck. I didn't know that. Brent --- Chuck Hards <chuckhards@yahoo.com> wrote:

--- UTAHDEB@aol.com wrote:

...

What's the difference between Enke's Division and Enke's Minima?

Debbie

Debbie, Enke's Minima is a low-contrast feature in the middle of the A-Ring, sometimes appearing as ring segments, or a band barely discernable from the surrounding Ring. Enke's Division is seen as a true gap near the outer edge of the A-Ring.

Chuck

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I still have the 22 inch, but I use it only about once every three of four years. I have only seen one or two nights in the 20 odd years I have had it where the seeing would let it perform well on the planets. It would be good to get it a home where it was used more often. On the two occasions when I have seen the spokes I was using a 12.5 inch scope. Once with a friend's scope, and once with mine. One time was at Little Mountain and the other was at Stansbury, I believe. Enke's division I have seen several times with a 6" refractor, my 8" refractor, the 9" CLark, and my 12.5 inch scope. Brent --- Chuck Hards <chuckhards@yahoo.com> wrote:

You're welcome, Brent.

Now's the best time to look for Enke's minima. I have never seen it (or them) with conviction, although I've heard of it having been seen in 12.5" scopes. The minima are about as visible as the "spokes" in the B Ring (although of different form); in other words, not very. Large aperture and an excellent night are needed.

Brent, if you haven't sold that 22-inch yet, it's the perfect scope for Ring-scrutiny.

This is just a personal thought, but if you had a large enough aperture, a polarizing filter might affect visibility.

Chuck

--- Brent Watson <brentjwatson@yahoo.com> wrote:

...

Thanks, Chuck. I didn't know that. Brent

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That's a great site, Rich, how'd you find it? Google search? Has anyone on the list ever seen an Enke minima with certainty? This phenomenon should be much easier to detect with a digital camera. Contrast in the image can be stretched until it becomes visible. Has anyone been imaging Saturn and trying manipulation techniques on the file? Chuck --- Richard Tenney <retenney@yahoo.com> wrote:

Deb et al,

Here's a link with a good deal of detailed info about Encke's minima, divsion, etc:

http://home.fiam.net/ericj/encke.html

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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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