Which Is Best? - TV-102 Or FS-102

Dang it, with only two scopes, neither can be best.
Bill Meyers

"ValeryD" wrote in message


Absolutely correct. But... all depends also how easy an objective can be
re-centered and re-adjusted if something happens.

Markus can confirm, that 125mm F/8 Borg objective was damaged during
air-line trip. It was not only decentered, but also has a chip at the
ED lens (15x10mm).
The lens then was easily painted black at the chip and I was able to
re-center lenses within 15min. It will take only 5 min if only there
will be 3 centering screws instead of unusual four! :-)


V.D.
--------------
Valery,

would be nice if you write the full storry and not simple post it took
you 15 minutes to recenter.
First of all you could not fix the decentering at all. Only after you
drilled new
centering screws/holes in the cell you could get ridd of the problem,
right ?

Markus




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"Markus Ludes" wrote in message news:d1d9608618360d6ec13318ea51ed598b.30545@mygat e.mailgate.org...
"ValeryD" wrote in message


Absolutely correct. But... all depends also how easy an objective can be
re-centered and re-adjusted if something happens.

Markus can confirm, that 125mm F/8 Borg objective was damaged during
air-line trip. It was not only decentered, but also has a chip at the
ED lens (15x10mm).
The lens then was easily painted black at the chip and I was able to
re-center lenses within 15min. It will take only 5 min if only there
will be 3 centering screws instead of unusual four! :-)


V.D.
--------------
Valery,

would be nice if you write the full storry and not simple post it took
you 15 minutes to recenter.
First of all you could not fix the decentering at all. Only after you
drilled new
centering screws/holes in the cell you could get ridd of the problem,
right ?

Markus


No, may be you do not remember all exactly. I fixed the decentering
with four screws. But it was a challenge with four screws. Really.

When I wished to clean the lenses inside, I don't like to repeat this
challenge again. So, I drilled two new holes, made a thread in them
and with these three centering screws the task was easy like 1, 2, 3.


Valery Deryuzhin.

Hey, Maybe you two guys could write a book how on to re-center lens
touching on all details such as removing the lenses from the lens
cell and aligning each of them (for lens cell where no user centering
mechanism is available), also details about temperature compensated
cells, etc. It can be a good addition to Suiter's book "Star Testing
Astronomical Telescopes". Imagine a book called "Re-centering
Astronomical Telescopes" by Markus & Valery But then it may reveal
many trade secrets Thomas and Roland may not be so happy about.

If you remove one lens from a Triplet apo and view thru the remaining
two. I wonder what image one can expect to see... maybe an uncorrected
single color or all colors messed up depending on which lenses are
removed? I wonder if any telescope maker has given out the data of the
lenses or they are all kept top trade secret. But then if you remove each
lens and put white powder on it and run it thru a 3D laser scanner
to determine the exact shape of the lens. One can determine the curves,
etc. And by running many light into the lens, one can determine
the refractive index and Abbe numbers of the unknown lens, isn't it.

opti



"Markus Ludes" wrote in message news:d1d9608618360d6ec13318ea51ed598b.30545@mygat e.mailgate.org...
"ValeryD" wrote in message


Absolutely correct. But... all depends also how easy an objective can be
re-centered and re-adjusted if something happens.

Markus can confirm, that 125mm F/8 Borg objective was damaged during
air-line trip. It was not only decentered, but also has a chip at the
ED lens (15x10mm).
The lens then was easily painted black at the chip and I was able to
re-center lenses within 15min. It will take only 5 min if only there
will be 3 centering screws instead of unusual four! :-)


V.D.
--------------
Valery,

would be nice if you write the full storry and not simple post it took
you 15 minutes to recenter.
First of all you could not fix the decentering at all. Only after you
drilled new
centering screws/holes in the cell you could get ridd of the problem,
right ?

Markus

But then it may reveal
many trade secrets Thomas and Roland may not be so happy about.

If you remove one lens from a Triplet apo and view thru the remaining
two. I wonder what image one can expect to see... maybe an uncorrected
single color or all colors messed up depending on which lenses are
removed? I wonder if any telescope maker has given out the data of the
lenses or they are all kept top trade secret. But then if you remove each
lens and put white powder on it and run it thru a 3D laser scanner
to determine the exact shape of the lens. One can determine the curves,
etc. And by running many light into the lens, one can determine
the refractive index and Abbe numbers of the unknown lens, isn't it.


WOW, I'm speechless! Will wonders never cease?

RC

On 28 Jul 2003 15:15:22 -0700, (optidud) wrote:

Hey, Maybe you two guys could write a book how on to re-center lens
touching on all details such as removing the lenses from the lens
cell and aligning each of them (for lens cell where no user centering
mechanism is available), also details about temperature compensated
cells, etc. It can be a good addition to Suiter's book "Star Testing
Astronomical Telescopes". Imagine a book called "Re-centering
Astronomical Telescopes" by Markus & Valery But then it may reveal
many trade secrets Thomas and Roland may not be so happy about.

If you remove one lens from a Triplet apo and view thru the remaining
two. I wonder what image one can expect to see... maybe an uncorrected
single color or all colors messed up depending on which lenses are
removed? I wonder if any telescope maker has given out the data of the
lenses or they are all kept top trade secret. But then if you remove each
lens and put white powder on it and run it thru a 3D laser scanner
to determine the exact shape of the lens. One can determine the curves,
etc. And by running many light into the lens, one can determine
the refractive index and Abbe numbers of the unknown lens, isn't it.

opti


Try reversing the elements and also try different types of liquid
to space the elements. Just for fun, of course.
-Rich