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| Rich... |
 Posted: Tue Oct 27, 2009 6:43 pm |
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I can't believe what they've done with the current C8's. The CPC is a
hulking. plastic-clad PIG of a scope. Compare it to a mid-1970's C8. Even
if you added computer-guided drive motors on both axis, it wouldn't be
anywhere near as CHEAP-looking and walrus-like as the new Chinese or
Mexican (which?) Celestron. Thank GOD the optics today tend to be pretty
good and pretty consistent, that's one good thing. |
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| Quadibloc... |
| Posted: Tue Oct 27, 2009 6:43 pm |
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On Oct 27, 6:43 pm, Rich <n... at (no spam) nowhere.com> wrote:
[quote]Thank GOD the optics today tend to be pretty
good and pretty consistent, that's one good thing.
[/quote]
The fact that the new Celestrons now have aplanatic optics, like Meade
introduced to the mass market, is positive.
But I'm not happy that there seems no longer to be such a thing as an
equatorial fork mount - except as an option that loses some of the
features of the mount. Of course, Meade (but not Celestron) has an
image rotator (well, a camera hanging off the eyepiece rotator), which
is even better.
John Savard |
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| Quadibloc... |
| Posted: Tue Oct 27, 2009 7:17 pm |
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On Oct 27, 11:08 pm, Chris L Peterson <c... at (no spam) alumni.caltech.edu> wrote:
[quote]On Tue, 27 Oct 2009 21:29:18 -0700 (PDT), Quadibloc <jsav... at (no spam) ecn.ab.ca
wrote:
Of course, Meade (but not Celestron) has an
image rotator (well, a camera hanging off the eyepiece rotator), which
is even better.
How so? While big pro scopes use sophisticated instrument rotators, they
are pretty much a nightmare for amateur imagers. You replace one
steadily driven axis with three that need to be precisely controlled-
all with PE to worry about-, and make active guiding very difficult as
well. Altaz mounts with rotators are great for meter-class scopes, but
are not the way to go for smaller, amateur instruments. You can't beat
an equatorial fork for that, or a GEM as a second choice.
[/quote]
You do have a valid point. Meade's rotator is controlled by the go-to
telescope mount, and when the digital camera is small and light, it
seemed to me that this would be a nice stable set-up combined with an
alt-azimuth fork mount. But if one is considering active guiding,
then, yes, I admit there's no alternative to a properly polar-aligned
equatorial mount.
John Savard |
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| Chris.B... |
| Posted: Tue Oct 27, 2009 9:43 pm |
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Is Celestron, like art and classical music, the absolute proof that
time is running backwards. ;-)
Will a backlash ensue leading to a revolting resurgence in cardboard,
classical refractors? :-)
Answers on a postcard, please, to s.a.a. |
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| Chris L Peterson... |
| Posted: Tue Oct 27, 2009 11:08 pm |
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On Tue, 27 Oct 2009 21:29:18 -0700 (PDT), Quadibloc <jsavard at (no spam) ecn.ab.ca>
wrote:
[quote]Of course, Meade (but not Celestron) has an
image rotator (well, a camera hanging off the eyepiece rotator), which
is even better.
[/quote]
How so? While big pro scopes use sophisticated instrument rotators, they
are pretty much a nightmare for amateur imagers. You replace one
steadily driven axis with three that need to be precisely controlled-
all with PE to worry about-, and make active guiding very difficult as
well. Altaz mounts with rotators are great for meter-class scopes, but
are not the way to go for smaller, amateur instruments. You can't beat
an equatorial fork for that, or a GEM as a second choice.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com |
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| Chris L Peterson... |
| Posted: Tue Oct 27, 2009 11:11 pm |
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On Tue, 27 Oct 2009 19:43:42 -0500, Rich <none at (no spam) nowhere.com> wrote:
[quote]I can't believe what they've done with the current C8's. The CPC is a
hulking. plastic-clad PIG of a scope. Compare it to a mid-1970's C8. Even
if you added computer-guided drive motors on both axis, it wouldn't be
anywhere near as CHEAP-looking and walrus-like as the new Chinese or
Mexican (which?) Celestron. Thank GOD the optics today tend to be pretty
good and pretty consistent, that's one good thing.
[/quote]
They have good optics, and they have good tracking. Who cares what they
look like, if they get the job done. I'd take a modern, computerized
mount over what you got on a 1970's C8, which would be pretty worthless
to a modern imager.
(You must be one bitter, miserable SOB... have you ever had anything
positive to say about anything?)
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com |
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| yourmommycalled... |
| Posted: Wed Oct 28, 2009 5:36 am |
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On Oct 28, 12:11 am, Chris L Peterson <c... at (no spam) alumni.caltech.edu> wrote:
[quote]On Tue, 27 Oct 2009 19:43:42 -0500, Rich <n... at (no spam) nowhere.com> wrote:
I can't believe what they've done with the current C8's. The CPC is a
hulking. plastic-clad PIG of a scope. Compare it to a mid-1970's C8. Even
if you added computer-guided drive motors on both axis, it wouldn't be
anywhere near as CHEAP-looking and walrus-like as the new Chinese or
Mexican (which?) Celestron. Thank GOD the optics today tend to be pretty
good and pretty consistent, that's one good thing.
They have good optics, and they have good tracking. Who cares what they
look like, if they get the job done. I'd take a modern, computerized
mount over what you got on a 1970's C8, which would be pretty worthless
to a modern imager.
(You must be one bitter, miserable SOB... have you ever had anything
positive to say about anything?)
_________________________________________________
Chris L Peterson
Cloudbait Observatoryhttp://www.cloudbait.com
[/quote]
In this case Chris I agree with you. Indeed the current generation
SCT uses a lot of plastic as shrouds, but the core of the Celestron is
actually well made. I've always preferred equatorial mounts regardless
of how much the dob fanbois jump up and down about how easy to use
they aren't. My own preference is for a fork, but that maybe because I
mounted the first mirror I made on a fork. |
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| Uber Buble... |
| Posted: Wed Oct 28, 2009 7:17 am |
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He was born with a stick-in-da-ass. Nothing can be done.
"Chris L Peterson" <clp at (no spam) alumni.caltech.edu> wrote in message
news:9ekfe5lkst21835usgl5mv0f219o8mmsov at (no spam) 4ax.com...
[quote]On Tue, 27 Oct 2009 19:43:42 -0500, Rich <none at (no spam) nowhere.com> wrote:
I can't believe what they've done with the current C8's. The CPC is a
hulking. plastic-clad PIG of a scope. Compare it to a mid-1970's C8.
Even
if you added computer-guided drive motors on both axis, it wouldn't be
anywhere near as CHEAP-looking and walrus-like as the new Chinese or
Mexican (which?) Celestron. Thank GOD the optics today tend to be pretty
good and pretty consistent, that's one good thing.
They have good optics, and they have good tracking. Who cares what they
look like, if they get the job done. I'd take a modern, computerized
mount over what you got on a 1970's C8, which would be pretty worthless
to a modern imager.
(You must be one bitter, miserable SOB... have you ever had anything
positive to say about anything?)
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com[/quote] |
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| Davoud... |
| Posted: Wed Oct 28, 2009 8:38 am |
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Chris L Peterson wrote:
[quote]You can't beat
an equatorial fork for that, or a GEM as a second choice.
[/quote]
How is it that you keep saying that apples are better than oranges?
Would it not be more accurate to say that, as a practical matter, you
must have a GEM if you are using a refractor?
And that you can't beat an equatorial fork if you are prepared to spend
upwards of $12-15k for a quality mount _and_ if you are using a
reflector (except for a long-tube reflector)?
And that a fork is a requirement for a large (observatory-class)
reflector?
And that you can't beat a GEM if you want to get a quality mount for
under $12-15k and/or you have a refractor?
One can reduce the stated prices some if one is not doing
astrophotography, but in any case one will not be putting a refractor
on a fork unless one has access to a precision machine shop and is
prepared to design and build the fork oneself -- in which case one may
be looking at _serious_ money. Cheaper to let Astro Physics or Bisque
do the work for you.
To simplify the matter -- and you know I need things to be made simple
-- I would summarize thusly:
Refractor -- GEM.
Most consumer-size reflectors: Fork or GEM.
Large reflectors
<http://www.company7.com/mccmo/graphics/ogs.rc24neaf_682958.jpg>: Fork.
To sum up the summing up, I see one instance in which a fork is a
necessity, one instance in which a GEM is a necessity, and one instance
in which personal preference is in play. I cannot derive from that that
either mount is better than the other.
Except that, for those amateurs who require a measure of versatility,
the GEM is the only choice. My GEM can handle any of my three
refractors or my three reflectors, or combinations thereof, and the
change can be done quickly via Losmandy dovetails. I don't believe that
can be said of any affordable fork mount.
To add to the summing up, I would note that my miserable and unworthy
page on removing a Meade OTA from its fork and putting it on a GEM
<http://www.primordial-light.com/meadeotaremoval-1.html> generates a
certain amount e-mail. To date no one has asked about going the other
direction.
Finally, and I mean
Davoud
--
I agree with everything that you have said and everything that
you will say in your entire life.
usenet *at* davidillig dawt cawm |
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| Chris L Peterson... |
| Posted: Wed Oct 28, 2009 10:17 am |
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On Wed, 28 Oct 2009 10:38:22 -0400, Davoud <star at (no spam) sky.net> wrote:
[quote]Chris L Peterson wrote:
You can't beat
an equatorial fork for that, or a GEM as a second choice.
How is it that you keep saying that apples are better than oranges?
Would it not be more accurate to say that, as a practical matter, you
must have a GEM if you are using a refractor?
[/quote]
I wouldn't say "must", but that's a fair assessment most of the time.
I don't really disagree with your comments; you've focused on the
practical, and I was speaking abstractly. And abstractly- where we don't
need to consider specific telescope forms or specific economics, I'd
argue that you can't beat a fork for imaging. Furthermore (and also
abstractly), a fork is kinematically a better design than a GEM, with
its unfortunately cantilevered axes.
Of course, the key point wasn't a comparison between forks and GEMs at
all, but an argument in favor of an equatorial mount for imaging, as
compared with an altaz mount and instrument rotator.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com |
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| Rich... |
| Posted: Wed Oct 28, 2009 5:04 pm |
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Chris L Peterson <clp at (no spam) alumni.caltech.edu> wrote in
news:9ekfe5lkst21835usgl5mv0f219o8mmsov at (no spam) 4ax.com:
[quote]On Tue, 27 Oct 2009 19:43:42 -0500, Rich <none at (no spam) nowhere.com> wrote:
I can't believe what they've done with the current C8's. The CPC is a
hulking. plastic-clad PIG of a scope. Compare it to a mid-1970's C8.
Even if you added computer-guided drive motors on both axis, it
wouldn't be anywhere near as CHEAP-looking and walrus-like as the new
Chinese or Mexican (which?) Celestron. Thank GOD the optics today
tend to be pretty good and pretty consistent, that's one good thing.
They have good optics, and they have good tracking. Who cares what
they look like, if they get the job done. I'd take a modern,
computerized mount over what you got on a 1970's C8, which would be
pretty worthless to a modern imager.
(You must be one bitter, miserable SOB... have you ever had anything
positive to say about anything?)
[/quote]
I could tell you something, but I don't speak sheep. |
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| yourmommycalled... |
| Posted: Wed Oct 28, 2009 6:53 pm |
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Guest
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On Oct 28, 6:04 pm, Rich <n... at (no spam) nowhere.com> wrote:
[quote]Chris L Peterson <c... at (no spam) alumni.caltech.edu> wrote innews:9ekfe5lkst21835usgl5mv0f219o8mmsov at (no spam) 4ax.com:
On Tue, 27 Oct 2009 19:43:42 -0500, Rich <n... at (no spam) nowhere.com> wrote:
I can't believe what they've done with the current C8's. The CPC is a
hulking. plastic-clad PIG of a scope. Compare it to a mid-1970's C8.
Even if you added computer-guided drive motors on both axis, it
wouldn't be anywhere near as CHEAP-looking and walrus-like as the new
Chinese or Mexican (which?) Celestron. Thank GOD the optics today
tend to be pretty good and pretty consistent, that's one good thing.
They have good optics, and they have good tracking. Who cares what
they look like, if they get the job done. I'd take a modern,
computerized mount over what you got on a 1970's C8, which would be
pretty worthless to a modern imager.
(You must be one bitter, miserable SOB... have you ever had anything
positive to say about anything?)
I could tell you something, but I don't speak sheep.
[/quote]
Indeed you mindlessly repeat what you hear elsewhere like a parrot,
other than that you don't speak at all |
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| Too_Many_Tools... |
| Posted: Wed Oct 28, 2009 7:17 pm |
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On Oct 28, 12:08 am, Chris L Peterson <c... at (no spam) alumni.caltech.edu> wrote:
[quote]On Tue, 27 Oct 2009 21:29:18 -0700 (PDT), Quadibloc <jsav... at (no spam) ecn.ab.ca
wrote:
Of course, Meade (but not Celestron) has an
image rotator (well, a camera hanging off the eyepiece rotator), which
is even better.
How so? While big pro scopes use sophisticated instrument rotators, they
are pretty much a nightmare for amateur imagers. You replace one
steadily driven axis with three that need to be precisely controlled-
all with PE to worry about-, and make active guiding very difficult as
well. Altaz mounts with rotators are great for meter-class scopes, but
are not the way to go for smaller, amateur instruments. You can't beat
an equatorial fork for that, or a GEM as a second choice.
_________________________________________________
Chris L Peterson
Cloudbait Observatoryhttp://www.cloudbait.com
[/quote]
I agree.
TMT |
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| Davoud... |
| Posted: Wed Oct 28, 2009 10:08 pm |
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Davoud:
[quote]How is it that you keep saying that apples are better than oranges?
Would it not be more accurate to say that, as a practical matter, you
must have a GEM if you are using a refractor?
[/quote]
Chris L Peterson:
[quote]I wouldn't say "must", but that's a fair assessment most of the time.
[/quote]
I would like to see or read about a six-inch refractor on a fork mount.
[quote]I don't really disagree with your comments; you've focused on the
practical, and I was speaking abstractly. And abstractly- where we don't
need to consider specific telescope forms or specific economics, I'd
argue that you can't beat a fork for imaging. Furthermore (and also
abstractly), a fork is kinematically a better design than a GEM, with
its unfortunately cantilevered axes.
[/quote]
Ah, yes, well.... It goes back to one's upbringing, do'n' it? You were
wealthy, we were poor. You had abstractions. We couldn't afford
abstractions; we had to make do with practical stuff -- what worked in
the real world. You pondered specific telescopes and specific economics
while we stood in line pondering surplus rice and worried all night
about where the next eyepiece was coming from. You had kinematics, we
had second-hand shoes.
Cantilevered axes are unfortunate, really? The GEM system is
mechanically simple and it works. Sounds like another of your kinematic
abstractions, you wealthy person who didn't know the meaning of
"unfortunate." Except in the abstract, of course!
[quote]Of course, the key point wasn't a comparison between forks and GEMs at
all, but an argument in favor of an equatorial mount for imaging, as
compared with an altaz mount and instrument rotator.
[/quote]
We knew that. We weren't _that_ poor. The desperately poor people in
the next coal patch down the trail all had alt-az mounts and instrument
rotators.
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 L Peterson... |
| Posted: Wed Oct 28, 2009 10:58 pm |
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On Thu, 29 Oct 2009 00:08:42 -0400, Davoud <star at (no spam) sky.net> wrote:
[quote]Ah, yes, well.... It goes back to one's upbringing, do'n' it? You were
wealthy, we were poor. You had abstractions.
[/quote]
Sounds like you are (abstractly) telling me where to put my silver
spoon!
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com |
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