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SL3telescope
- From: P3D Peter Abrahams <telscope@xxxxxxxxxx>
- Subject: SL3telescope
- Date: Thu, 17 Oct 96 00:38 PDT
>Peter Abrahams. Wouldn't it help you to have a 3-D telescope to reduce
>that atmospheric noise you look through?
> mailto:wc@xxxxxxxxxxxx
Now, if this had come from one of the big kidders on the list, I would have
kept scrolling. But it does reflect a few of the realities of telescopy:
--one way to focus or collimate a telescope is to make an aperture mask, a
piece of cardboard the diameter of the objective (remembering that amateur
telescopes these days are commonly 10 to 30 inch aperture). Two holes,
maybe 2 inches each, and on opposite ends of a diameter, let in the image of
a star. As you focus or adjust collimation, the two stars move towards each
other, and when they coincide, you are focused or collimated. Is this relevant?
--the effects of atmospheric turbulence are diminished by reducing aperture,
and two+ small holes show less turbulence than one hole of the same area
(you want to be smaller than the air cells causing twinkling of light.) Now
we get speculative......any additional information in the image would raise
signal/noise ratio & sort of help. But z-axis information......is a long
stretch.
--I am one of those misbegotten waifs who can't get a grip on SL3D, even
though I must be the only subscriber who has read every diatribe on the
subject on this list. But, surely SL3D must be limited to macro or other
situations where a limited stereo base is appropriate. And these are
astronomical instruments.
--Did you know....file: many amateur astronomers have reported seeing the
jet stream and other turbulence in their telescopes. I assume this is some
unusual lighting producing something like Schlieren images.
--This has been somewhat off topic. But the use of stereo imaging to
increase signal to noise ratio by packing more information in an image, if
it is possible at all, is fascinating. My new scanner has an optical
resolution of 600 dpi and an interpolated resolution of 1200. I wonder if
that is analogous, if only to a poet.
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Peter Abrahams telscope@xxxxxxxxxx
the history of the telescope, the microscope,
and the prism binocular
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