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| Pierre Vandevenne... |
 Posted: Thu Oct 29, 2009 12:27 pm |
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On Oct 29, 5:58 am, Chris L Peterson <c... at (no spam) alumni.caltech.edu> wrote:
[quote]On Thu, 29 Oct 2009 00:08:42 -0400, Davoud <s... at (no spam) sky.net> wrote:
Ah, yes, well.... It goes back to one's upbringing, do'n' it? You were
wealthy, we were poor. You had abstractions.
Sounds like you are (abstractly) telling me where to put my silver
spoon!
[/quote]
Are you guys staging an argument solely for credibility purposes?  |
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| Sketcher... |
| Posted: Thu Oct 29, 2009 3:43 pm |
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Davoud wrote:
[quote]
I would like to see or read about a six-inch refractor on a fork mount.
"Star Testing Astronomical Telescopes" by Suiter (first edition, 2nd[/quote]
printing) shows on the back cover a photo of the author standing
beside a six-inch refractor on a fork (alt-az) mount.
Sketcher,
To sketch is to see. |
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| Davoud... |
| Posted: Thu Oct 29, 2009 6:30 pm |
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Pierre Vandevenne:
[quote]Are you guys staging an argument solely for credibility purposes?
[/quote]
If it don't look like a disagreement and it don't walk like a
disagreement and it don't quack like a disagreement, chances are it
wasn't staged to persuade anyone that it was a disagreement.
Nowadays Mr. Peterson and I conduct our bitter disputes via personal
e-mail in order to spare the group -- indeed, the entire human
population -- from exposure to the shocking language that we are apt to
use. How shocking? I can't tell you directly, but I will say that one
recent exchange corrupted the registry on Mr. Peterson's Windows
machine and damaged the HD on my Mac. E-mails leaked by our respective
staffs have led to our being threatened with legal action by Apple, MS,
Dell, Commodore, Sinclair, the FCC, the FTC, the FDA, the FAA, the NSA,
the Holy See, the RNC, NIST, the "Christian" Coalition, the National
Association of Fork Users, the American Council on GEM's, A-P, Meade,
and Sears.
Davoud
--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.
usenet *at* davidillig dawt cawm |
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| Chris.B... |
| Posted: Fri Oct 30, 2009 4:24 am |
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On Oct 30, 2:43 am, Sketcher <astrosketc... at (no spam) gmail.com> wrote:
[quote]Davoud wrote:
I would like to see or read about a six-inch refractor on a fork mount.
"Star Testing Astronomical Telescopes" by Suiter (first edition, 2nd
printing) shows on the back cover a photo of the author standing
beside a six-inch refractor on a fork (alt-az) mount.
Sketcher,
To sketch is to see.
[/quote]
It only requires to be offset enough for the OTA to clear the polar
axis for an equatorial fork to offer full sky observation.
It also requires much lighter counterweights than a German mounting if
greater portability are required. |
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| Chris L Peterson... |
| Posted: Fri Oct 30, 2009 10:08 am |
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On Fri, 30 Oct 2009 07:24:34 -0700 (PDT), "Chris.B" <chris.b at (no spam) nypost.dk>
wrote:
[quote]It only requires to be offset enough for the OTA to clear the polar
axis for an equatorial fork to offer full sky observation.
[/quote]
A fork mount is a perfectly reasonable design to use even for a long
refractor. But because of the wide variation in mount designs for
different OTAs, it isn't a very good design for a mount manufacturer
looking to provide product to a wide market segment. So it is quite
natural that most mount makers sell GEMs, which are intrinsically
friendly to virtually all scope types.
It doesn't matter if a fork is a somewhat better design, and provides
somewhat better performance for imagers, if the economics of the
situation make it difficult for anybody to produce a general purpose
product. That's why commercial forks are quite a bit more expensive.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com |
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| Davoud... |
| Posted: Fri Oct 30, 2009 11:19 am |
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Davoud:
[quote]I would like to see or read about a six-inch refractor on a fork mount.
[/quote]
Sketcher:
[quote]"Star Testing Astronomical Telescopes" by Suiter (first edition, 2nd
printing) shows on the back cover a photo of the author standing
beside a six-inch refractor on a fork (alt-az) mount.
[/quote]
Thanks. I'm sorry I don't have a copy of that, so I won't be able to
see it. I take it that it was computer-controlled. Do you happen to
know where I can find images made with that 'scope and mount?
Chris.B:
[quote]It only requires to be offset enough for the OTA to clear the polar
axis for an equatorial fork to offer full sky observation.
[/quote]
Is that all? Then I only need to run down to the local fork-mount store
and pick up a mount with 1.5-meter-tall arms and a load capacity of 64
kg to hold this
<http://www.primordial-light.com/technique.html#toafsq>? It'll be on
the shelf and cost no more than... I don't know, you tell me what you
would charge me for such a mount. Keep in mind that it isn't really on
your shelf; you will build it by hand. Include shipping from Denmark
and figure 2000 kg to include packing. I require computer control and,
at the price you will charge, precision not less than that offered by
the finest of the big-observatory-grade mounts.
Master ATM David Harbour worked on a beautiful large fork mount for
several years, but he reported that he gave up short of finishing it.
It is similar to what I would require, except Mr. Habrour was building
for a reflector and the clearance under the pivot is too short for my
purposes.
<http://www.atmsite.org/contrib/Harbour/Photos,%20med/ROLL2JPEG-11.JPG>
[quote]It also requires much lighter counterweights than a German mounting if
greater portability are required.
[/quote]
Portability would not be an issue in a fork capable of holding my
'scope; it would be every bit as portable as this mount is portable
<<http://www.company7.com/mccmo/graphics/ogs.rc24neaf_682958.jpg>;
i.e., it would require a flatbed truck with crane. In the case of Mr.
Harbour's mount one could eliminate the flatbed if one had the
wherewithal to construct a railroad. Very convenient. With land
purchases, bridge construction, and the like I could construct a track
to my club's observing site for as little as $400 million.
I think I'll stand with my assertion that, as a practical matter --
hypotheses and abstractions counting for nothing because they won't
support a telescope -- a GEM is the only way to mount a refractor of
any size.
Davoud
--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.
usenet *at* davidillig dawt cawm |
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| Chris.B... |
| Posted: Sat Oct 31, 2009 11:09 pm |
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On Oct 30, 6:19 pm, Davoud <s... at (no spam) sky.net> wrote:
[quote]
I think I'll stand with my assertion that, as a practical matter --
hypotheses and abstractions counting for nothing because they won't
support a telescope -- a GEM is the only way to mount a refractor of
any size.
Davoud
--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.
[/quote]
Aw c'mon. You promised, in the subtitles, to agree with me.
Good post, though.  |
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