Posts Made By: Dan D DuBal

Ignoring true/actual scope limitations for just a moment, and considering your own preferences in stargazing (targets, favorites)...

...what's the very first goodie you'd want to look at (and stare at), through the 11GPS? How about the TV101?

Do *you* have a favorite among the scopes you listed? If so, why? What makes it your favorite?

Do you enjoy the 10-incher?

Are you looking for something *somewhat* more portable (such as a C9.25), or *a lot* more portable (such as the TV101)?

Some of the above questions may be easier to consider & ponder than, say, a single daunting question like "What's your ideal scope?" Several more specific questions may offer "easier" help when trying to analyze your goals or hopes.

Putting myself in your shoes, I'd be tempted to go after a TEC6, or Mewlon 180. Either would be quite at home (and very grin-worthy) atop the GM-8. The Mewlon 210 ups the ante, but it may be nearing the "too bulky" realm for you.

Best wishes and luck, Jared.
-Dan

I remember coming across that episode (re-run, of course) some 30 years ago. I missed the first segment or two, so I didn't see Mr. Wilson's purchase or his showing Dennis the ropes. However, those glow-in-the-dark "burp" balls are chiseled into my brain and will likely never fade. While I recall the special-effect "flight" of each ball through Mr. Wilson's field of view as being "rough" and quite un-satellite-like, the writer(s)/director(s) *do* deserve some credit for at least keeping that telescopic field of view realistically *small* & narrow.

I don't recall any background stars during the "satellite" views -- *were* there any?

Best wishes and thanks for sharing.
-Dan

I know of no other persons having experience with Drappell's refractors. Check Cloudy Nights for last month's article about the 8-inch "Travel Star" (written by Drappell, himself).

I must admit, however, that I am unable to swallow the author's claims that he saw no false color whilst viewing Jupiter and Luna. -Actually, I should qualify that... If he truly did not see false color, I'm left to wonder about one or more of the following factors: his eyesight, his recollection, exit pupil (effective aperture), or the objective's coatings.

Regardless -- the scopes themselves look quite intriguing and attractive.

Cheers and best wishes.
-Dan

MK67s of recent vintage (last ~four years) are indeed designed for 2-inch diagonal use as a standard (i.e. focal plane sits around ~four inches behind rear of focuser housing). A two-inch extender (both diameter and length) will set the scope up for use with 1.25-inch diagonals. I use the Intes 2-inch extender with a Lumicon 1.25-inch diagonal, and this set up -- so far, anyway -- has accomodated every .965- and/or 1.25-inch eyepiece I've tried. That list includes more than 30 eyepieces of various designs, ranging from 4mm thru 35mm.

With max-field 2-inchers, an MK67 may gain an additional ~half degree (50% wider) over a max-field 1.25-incher's field.

I wouldn't say you'd be "better off" with *either* configuration, so long as the diagonal in question is excellent.

Since you're thinking "maybe" about a 2-inch eyepiece later, perhaps it makes more sense to "maybe" add a 2-inch diagonal at that time -- in the future -- rather than right off the bat.

Best wishes.
-Dan

Unfortunately, there are many factors which govern the "use-ability" of most microscope eyepiece designs in telescopic systems. Perhaps the biggest differences/considerations involve "compensating" microscope eyepieces, which are designed to work with (to compensate for) optical characteristics & aberrations inherent to particular microscope objective designs. As such, many folks are wary of (or simply avoid) compensating -- a "K-Pl" eyepiece, for example (compensating plan/flat field). I don't have enough experience with compensating designs to offer any insight beyond that generalization. I'm sure there are compensating eyepieces which work perfectly well with scopes, but they certainly bear stricter consideration than non-compensating eyepieces. The Nikon 10x "CWN" eyepiece (from APM) may be a compensating design; I'm not sure.

I'm unaware of any current Zeiss microscope eyepiece which is specified as an Abbe orthoscopic. Most are indeed orthoscopic (distortionless), but their designs differ from the traditional Abbe design. For this reason, I wouldn't expect them to be indistinguishable. Not saying they're *not* -- just wouldn't expect it.

On the other hand, "different" may not mean lesser or worse. In the case of the 10x offerings from APM, for example, there are folks who find them to offer superior fidelity when compared to the 25mm Abbe Orthoscopic. Of course, this is another tough call, as a 25mm eyepiece yields lower mags, making critical observation of low-contrast planetary detail even more difficult.

Perhaps a few "guidelines" may be suggested:

-With microscope eyepieces (even moreso than with telescope eyepieces), the "try before buy" rule is essential. Luckily, there are folks like Markus who do much of the trial work for the rest of us.

-Most modern microscope eyepieces *not* designated as "compensating" will do well in most telescopes. Simpler designations such as "Plan" and "Wide Plan" are usually good bets. Nikon, Olympus, & Zeiss are the most-popular brands among stargazers. Kellner-variant & Konig-variant designs remain numerous & popular in the microscope industry. There are plenty older microscope eyepieces utilizing Huygenian & Huygenian-variant designs; these usually require extreme (long) focal ratios for good performance.

Hope that's not too much babble. :-)
Best wishes.
-Dan

Hi, Tom.
Couple questions:

What brand/model is your SCT diagonal?

What's the inside diameter (as near as you can determine) of the socket you exposed when the barrel was removed (i.e. what's the outside diameter of *that* end of the barrel? You said "I guess it's a 2-inch ID but threaded on the outside..." (just want to make sure we're understanding what you're finding).

Depending on the diameter and threads, you may be able to simply use an existing SCT push-fit adapter, a standard diagonal barrel (from the same brand/company), or maybe an eyepiece barrel. If so, one of those items can be had fairly easily & cheaply.

Regarding the MK67 -- that infamous back focus concerns 1.25-inch diagonals, for the most part. A 2-inch diagonal should "gobble up" that extra back focus very nicely, so I wouldn't expect it to need an extra-long 2-inch diagonal barrel at all.

I think we can figure some things out and help determine your best (most convenient) course of action.

Best wishes and luck.
-Dan

<>

I think this a key aspect of that "endless search" scenario, Alan. Too often, the perceived "need" is based on (&/or related to) the successes of others, & the credit for those successes is much-too-heavily biased towards equipment. Skill & experience are discounted *far* too much. I see this same scenario in many other recreational pursuits & hobbies: golf, bowling, bicycling, photography, home/car audio, etc... Seems the notion is that greater success (hence greater satisfaction & joy) is more easily attained via "better" (&/or more) equipment. Tools over skills.

I believe I rebel against this notion a little (almost subconciously, at times) whenever I go off on one of my "small scope" bents, pushing the limits of 2- and 3-inch apertures.

The "perfect scope?" If the idea is that the perfect scope is one which feeds an observer perfect joy, then, hey -- I already it. Actually, I have a few of them.

If I were to end up being "stuck with" and "limited by" my 60mm, 75mm, and 150mm scopes (as well as my modest binoculars), for the rest of my life, I'm certain their "perfection" would never die.

Cheers and best wishes.
-Dan

I believe the only way to introduce a standard 48mm filter into a Barcon/Binocular Viewer set-up is either:
-via threaded extension tube ("ahead" of either Barcon lens assembly or complete Barcon)
-via threaded tapered nosepiece (with or without Baader diagonal - "behind" complete Barcon)

Other custom options (adapters or coupling rings) are possible, given thread compatibilities (Barcon, filter, custom adapter, diagonal housing &/or bayonet ring).

Hope that helps.
Best wishes and luck.
-Dan

Sal's not even close to being a Shawn wannabe.

McMaster-Carr is one source.
(mcmaster dot com)

Cheers.
-Dan