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Posts Made By: Mike Hosea

June 15, 2002 03:02 AM Forum: Telescope Making

dob bearings

Posted By Mike Hosea
Look for an S&T article in the last year or so--"An elegant 3-point Dobsonian" or similar title. I've thought of doing this but always concluded that it wasn't going to be worth the trouble for me.
--
Mike

July 8, 2002 10:53 PM Forum: Eyepieces

LENSPENS FOE SMALL EP's

Posted By Mike Hosea
There are two sizes, but I think either one will probably be too large. Despite having both sizes, I don't use either lens pen for anything. For small eye lenses I typically just blow off any debris with clean air, fog with my breath, and twist a fresh Q-tip (that specific brand) on the lens, leaning it one way and another to try to get some cotton fibers to clean the edges. I might repeat with a fresh Q-tip once or twice if I wasn't satisfied with the results. Always use a fresh Q-tip. Then I blow off any cotton fibers with clean air. Some liquid solvent could be used, but it is crucial that there not be enough of it moistening the Q-tip for capillary action to draw the liquid into the casing. It's a bit hard to control the quantity like that with small lenses.
--
Mike

July 20, 2002 12:55 AM Forum: Eyepieces

Re: Monocentric anyone?

Posted By Mike Hosea
You'll need a relatively slow scope to go with it. Shortest focal length at Edmund is 12.5mm.
--
Mike

July 25, 2002 03:54 AM Forum: Equipment Talk

Eyepiece Question

Posted By Mike Hosea
How about snagging one of the previously-loved 27mm Panoptics being dumped for the latest Nagler bimbo? ;-)

July 27, 2002 04:38 AM Forum: Eyepieces

Eye Relief of UO Orthos & Konigs

Posted By Mike Hosea
Don't know about the Konigs. I think you'll find the correct specs for the orthos on this page

http://www.kkohki.com/products/%83A%83C%83s%81%5B%83X%83X%83y%83b%83N

Eyepiece,Apparent field,Eye relief(mm),Weight(g)
OR.4, 41°, 3.5mm, 80g
OR.5, 43°, 4.0mm, 85g
OR.6, 43°, 4.8mm, 87g
OR.7, 42°, 5.6mm, 90g
OR.9, 42°, 7.2mm, 92g
OR.12.5, 44°, 10mm, 96g
OR.18, 46°, 14.4mm, 97g
OR.25, 47°, 20mm, 100g

August 4, 2002 09:19 PM Forum: Equipment Talk

Is this not possible ?

Posted By Mike Hosea
"... that costly?"

Yes, but I think a 10" Zambuto mirror (just the mirror) costs manufacturers something like a few hundred dollars more than other high-quality options. Some of the other added cost you see in these scopes reflects that they are hand made, some that higher quality components are being used. None of the PTMs using Zambuto mirrors can achieve the benefits that come with the economy of scale and manufacturing efficiency that Meade and Celestron enjoy. There's no point in trying because ZOC is a small operation incapable of supporting ANY growth in production.
--
Mike

August 19, 2002 01:58 AM Forum: Eyepieces

Circle-T, or Circle-V?

Posted By Mike Hosea
Circle-T is Kokusai Kohki, I think. See

http://www.kkohki.com/english/Kkohkiparts.html

though the logo may actually signify a subcontracting manufacturer. Circle-V is Vixen. Both companies sell a number of eyepieces. Never heard of Circle-A.

Note, it seems that Vixen orthos are likely to be Plossls rather than Abbes.
--
Mike

August 27, 2002 07:35 PM Forum: Eyepieces

New planetary ep essay and Edmund RKEs

Posted By Mike Hosea
No correction. I never said RKEs were 4-element eyepieces. RKEs are 3-element eyepieces (field doublet with eye singlet) with 4 air-to-glass surfaces. Obviously, the number of air-to-glass surfaces must always be an even number. What many people do not realize is that cemented interfaces are very efficient compared to air-to-glass surfaces, so the fact that, say, Plossls and Abbes have one additional element and one additional cemented interface doesn't handicap them much. Glass transparency is an issue that really should be modeled in, but it's not easy to do a good job of it without specific, technical data. I guess the best possible implementation of a Kellner or RKE should be able to edge out the best possible implementation of a Plossl or Abbe in transmission, but we're not usually comparing apples to apples like that, and different coatings, glasses, and surface smoothness and accuracy can make the difference.
--
Mike

September 3, 2002 04:28 PM Forum: Equipment Talk

4" instrument, a serious planetary scope it is!

Posted By Mike Hosea
I know the term "serious" is used a lot wrt scopes, but it really isn't the scope that is or isn't "serious", it's the observer. To a "serious" observer, the scope is just a tool. If you've got a job to do and need to tighten a nut, you might reach for an adjustable wrench near you on the counter top, but you probably wouldn't worry much about whether it was the optimally-sized adjustable wrench as long as it was big enough to tighten that particular nut.
--
Mike

September 7, 2002 03:05 AM Forum: Equipment Talk

TeleVue eyepiece/taiwan?

Posted By Mike Hosea
I think it's about half and half now. The new type 6 Naglers are made in Japan, other Naglers are made in Taiwan. Radians are made in Taiwan, Plossls in Japan. I think Panoptics are made in Taiwan. The Nagler Zoom is made in Japan. The Barlows are made in Japan. I think the Powermates are made in Japan also, but I really can't remember about those now.

I know there's always keen interest in this issue because in the old days there was apparently good reason to prefer Japan as the source. But I've seen no evidence that this has validity any longer wrt to these specific two possibilities, Japan versus Taiwan.
--
Mike

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