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Posts Made By: jess tauber

November 7, 2005 01:25 AM Forum: Astro Binoculars

collapsible binoculars

Posted By jess tauber
I have a question for folks- IF collapsible binoculars, using flat (so lightweight) gradient index lenses existed in decent apertures (50mm and up), would you prefer them to the more traditional heavy tubular models, assuming one could easily adjust collimation? I'm asking similar questions of people in the refractor crowd. Thanks.

Jess Tauber

November 8, 2005 07:57 PM Forum: Refractors

how to take off a Synta lens assembly, help

Posted By jess tauber
Hi. I have a 6" F/8 Synta OTA that was damaged in shipping. Can't take off the cell from the front since the rim of the housing was banged in. This was going to be half of a binoscope. Anyone out there know how to take off the objective assembly from the main tube? Thanks.

Jess Tauber
[email protected]

January 8, 2006 07:07 AM Forum: Telescope Making

image quality of optical fiber for astro use?

Posted By jess tauber
I have a question just off the top of my head (somewhere between Andromeda and Perseus): I've wondered whether one could use light fiber (such as is utilized in endoscopes in medicine) to carry stellar images between the primary and other lens elements. Obviously micro applications already exist- but are these materials good enough quality for astro viewing? For instance instead of a secondary mirror or astrographic film or digital camera could one mount a suitably ray corrected optic fiber bundle there instead, and then carry the image elsewhere?

Related questions- would flexing the bundle (assuming flexibility) distort the image? How much loss of brightness does distance create? I'm sure you can think of other issues.

Thanks in advance (and to everyone who has answered my other off the wall questions in the past- Happy 2006).

Jess Tauber

January 20, 2006 05:09 PM Forum: Mounts

extendable center columns for long refractors?

Posted By jess tauber
Hi. I've noticed that many late 19th and early 20th century refractors were mounted on tripods that had extendable (crankable) center columns, even sometimes when the mount head itself was equatorial. My question is, given the low positions many viewers are forced into with tripods commonly available these days, even with extentions, why more manufacturers haven't taken a lesson from the history books? This isn't brain science!

Does anyone know of modern models with such a feature, for long focus refractors, so that the viewer can remain standing? Thanks.

Jess Tauber


January 25, 2006 07:17 PM Forum: Telescope Making

eye relief relief

Posted By jess tauber
I was just reading the review in the news section of the 56mm ep, where the reviewer noted the very long eye relief of the ep in question. I also have some longer FL ep's and the review, plus my own experiences with these made me wonder whether there is such a thing as a telescoping ep extender that will variably close up the distance between ep top and comfortable viewing distance for different viewers and also keep out stray light.

Shouldn't be too hard to make?

Jess Tauber

February 2, 2006 06:36 AM Forum: Telescope Making

variable angle diagonal

Posted By jess tauber
Has anyone heard of ATM or commercially made variable angle diagonals? The idea occurred to me as a way of avoiding eating up final focus length as a series of diagonals might to achieve the same overall effect.

Jess Tauber

February 4, 2006 09:52 PM Forum: Refractors

if someone makes them, will you come?

Posted By jess tauber
For the past months I've been experimenting with fabrication methods for large, telescope-scale gradient index lenses. These would be ultrathin, ultralight, and if they became available relatively cheaply (you couldn't get one now unless you were prepared to slap down a six or more figure sum) the question is whether the refractor-oriented community might be willing to try them out, or would they be more likely to say 'thanks but no thanks' and stick to the tried-and-true, despite that meaning being limited to smaller apertures (remembering that I'm using reflector apertures as a benchmark)?

Wouldn't you like to be able to stare the mirror boys right in the face and say, 'analyze this!', aperture wise? Or maybe you just LIKE top-heavy?

A refractor is a refractor, regardless of lens type- so I'm curious to hear your thoughts on the matter.

Jess Tauber

February 9, 2006 03:17 AM Forum: Telescope Making

microscope focusers for ATM?

Posted By jess tauber
Hi once again- do any of you have experience with (or have any of you heard of) using old salvaged microscope focusers as parts to fashion telescopic ones? I'd be particularly interested in whether they could be used to create sled-type focusers for reflectors.

Thanks.
Jess Tauber

February 13, 2006 04:43 AM Forum: Telescope Making

question about prisms

Posted By jess tauber
Hi again- does anyone know how big a prism has to be before internal absorption becomes a real problem?

Thanks.
Jess Tauber

February 15, 2006 11:42 AM Forum: Telescope Making

thin spherical elements versus optical doubly flat

Posted By jess tauber
Another stupid question- which is more difficult to grind and figure: a very thin spherical element (or two or three depending on achro/apo, etc.) to make a high focal ratio lens, or an optical window with two parallel high quality flat faces?

Secondly, I understand the issues involved with mirrors of different focal ratios in terms of need to parabolize with fast ones, etc. How is this with lenses? Which are easier to make/figure- slow, medium, or fast ones?

All of this is with regard to my gradient index work- it may not be necessary to use a flat window, and if spherical elements are cheaper anyway (such as corrector plates) then one might want to just build on those rather than reinvent the wheel.

Thanks again.

Jess Tauber

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