Telescope Reviews: Zhumell 20x80

Hi Gordon:

While I am pretty busy right now, I feel your letter needs to be answered—especially since you are obviously addressing some of my concerns. So, here goes.

You said:

“If one wants to make a collimator, such as an unfolded version of the UBMM, in which a Newtonian or Cassegrain telescope with a target in its eyepiece holder would face a smaller scope, with the binoc to be tested/adjusted located between the two scopes . . .

My reply:

Even as much as you have talked about it, most people haven’t a CLUE what a UBMM is—folded or otherwise—and that doesn’t make them stupid. Like me, they just don’t care—and I own one! Now then, with as much as I have talked about collimation, do I wish people were more savvy about the issue? Yes! However, this is a free country and I don’t feel the need to ram it down their throats. That’s not what the list is about.

You continue:

“it is of quite practical, not "academic" interest, to know if the UBMM has a direct image of the target focused on its groundglass.”

Gordon, there are OTHER opinions in the world. Obviously, for you the subject matters a great deal, and that is TOTALLY fine. For most of the rest of us, it does not matter at all. And that, by definition, makes it impractical. By definition? Yes, definition!

You continue:

“Do you consider Hanna's writings in ATM III (Willmann-Bell) to be academic? Which academy teaches this subject?”

Well, that comes in two parts. First, yes I do. And I will share with you TWO dictionary definitions of “academic.” (EMPHASIS ADDED)

1) Hypothetical or theoretical and not expected to produce an immediate or PRACTICAL RESULT.

2) Marked by a NARROW FOCUS on or display of learning ESPECIALLY ITS TRIVIAL ASPECTS.

And then there is the, “Do you consider Hanna’s . . .” approach. To me it seems just like another of your non-productive challenges. With all due respect, I often get the impression that you are here for show and for that you need a sparring partner. Well, I have neither the time or interest to be a sparring partner—although to this point, I have been wearing soft gloves.

When I comes to optics, I am as well-read as yourself, own as many books as you do and some of the most noted telescope makers, optical engineers and binocular enthusiasts in the world send me Christmas cards. And yes, I know about Hanna. Volume III is at my right elbow at the moment.

But I have got a great deal for you. If you will stop alluding to me in your spurious challenges, I will not bother you or me with any further replies. I think that is a dandy idea—peaceful coexistence! Or, as Dr. Stephen R. Covey (Seven Habits of Highly Effective People) says: we can agree to disagree, AGREEABLY.

Cheers,

Bill

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William J. Cook, Chief Opticalman, USNR-Ret.
Founding Editor, Amateur Telescope Making Journal
20-year vet. of Captain's Nautical Supplies, Optics Dept. Mgr.
Optics Machanic, WG11-3306, Ft. Lewis, Tacoma,WA
Yata, Yata, Yata . . .