No problem. It took me 35 years to get some concepts! I may have a parallelogram for you this weekend. We can come up with something for a tripod if you strike-out completey. C. --- Jim Gibson <xajax99@yahoo.com> wrote:

Chuck

That was a good explanation. I believe that Brent Watson explained that to me once. It seems it takes me a couple more times to hear things than it used to for things to gel.

Thanks.

By the way, I went to a couple of DI s looking for a tripod. I my have to go to Salt Lake to look for one.

Jim

Chuck Hards <chuckhards@yahoo.com> wrote:Hi Jim:

Here's the deal:

50X-60X per inch of aperture is the accepted maximum useful magnification for any telescope.

At these powers, small details approach the diffraction-limit for any given aperture.

Excellent optics will allow a coherent image above that limit, but no additional detail will be seen, since the resolving power of the telescope has already been taken to it's limit. The image can get bigger, but you won't pick up further details.

853X is too high for a 12", you won't see any additional detail beyond that seen at 600X.

Make sense?

Chuck

--- Jim Gibson wrote:

...

Question for Rich Tenny (or anyone else)

I saw the new Televue products (41mm eyepiece etc) you mentioned last night at SLAS at:

http://www.televue.com/WSP2003/NewProdsJan2003/New_at_WSP2003.htm

...

I don’t currently have any hi-power stuff like the 3.5mm or the 2.5mm Nagler. I ran this little

program

...

at: http://www.csgnetwork.com/telescopemagcalc.html for a 12” mirror with an f7 focal length and a 2.5mm eyepiece. One of the calculations states that for this setup the “Maximum Useful Magnification” is 600x; however, the 2.5mm would provide 853x. I also recall from a previous conversation we had that someone told you in reference to the Mars opposition that it could take all of the power you could crank. How does all this square? Does the Maximum Useful Magnification mean that everything over 600x (in this case) will go soft? If (big if) I bought a 2.5mm Nagler, could I use it for anything else? I am thinking that such power would only be good for bright planets.

Jim Gibson

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