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Main
Date: 21 Sep 2006 20:15:18
From: Jim Klein
Subject: Buying a 10" LX200R
|
Hello,
For weight vs. portability issues and minimum aperture that I can
stand, I have decided on an LX200R as my next scope.
1. Can it be focued for best optical performance and then an
auxilliary focuser used installed which moves the camera/eyepiece
rather than moving the primary. Being a professional optical designer
for 30 years, I understand that there is an optimal P to S spacing for
best PSF.
2. Are there after market wedges which provide MAX vibrational damping
?
3. Finally, if there are reasons why this is a stupid or bad choice
(sans the $ involved) I would rather hear them now than after I buy.
Sincerely,
Jim Klein
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows and (soon) MAC OSX
Free KDP-2 (DEMO) downloadable!
1-818-507-5706 (Voice and Fax)
|
|
| |
Date: 21 Sep 2006 23:11:17
From: Craig M. Bobchin
Subject: Re: Buying a 10" LX200R
|
In article <jas5h2hbs4161lt10fngej58ep16l262sr@4ax.com >,
jameseklein@earthlink.net says...
> Hello,
>
> For weight vs. portability issues and minimum aperture that I can
> stand, I have decided on an LX200R as my next scope.
>
> 1. Can it be focued for best optical performance and then an
> auxilliary focuser used installed which moves the camera/eyepiece
> rather than moving the primary. Being a professional optical designer
> for 30 years, I understand that there is an optimal P to S spacing for
> best PSF.
Yes it can. In fact the LX200 series comes with a mirror lock knob that
you use once you have gotten focused. You can then use the standard Zero
Image shift Microfocuser for fine focusing. This is an electric crayford
focuser based in JMI's NGF-S model that works through the Autostar.
> 2. Are there after market wedges which provide MAX vibrational damping
> ?
Again there are several. Meade makes one that they updated when the RCX
series came out. It wil work with the LX200 series as well.
Ken Milburn makes the Milburn wedge which I had and it is very stable
and easy to use. Another good after market wedge is the Mettler wedge.
Search for these on these at Astromart and you might be able to find a
used one for sale.
> 3. Finally, if there are reasons why this is a stupid or bad choice
> (sans the $ involved) I would rather hear them now than after I buy.
If you want to get into imaging,there are better systems. Or if you have
to move the system a lot to observe you might get tired of hauling
around all the weight. Also if you get a wedge, don't forget
counterweights. I'd suggest the Losmandy system.
But I liked my LX-200 GPS, but I wanted a better imaging system. Hence
my pulling th etube and putting it on a G-11.
Craig
>
> Sincerely,
>
> Jim Klein
> James E. Klein
> jameseklein@earthlink.net
>
> Engineering Calculations
> http://www.ecalculations.com
> ecalculations@ecalculations.com
> Engineering Calculations is the home of
> the KDP-2 Optical Design Program
> for Windows and (soon) MAC OSX
> Free KDP-2 (DEMO) downloadable!
> 1-818-507-5706 (Voice and Fax)
>
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| | |
Date: 22 Sep 2006 00:59:40
From: Jim Klein
Subject: Re: Buying a 10" LX200R
|
Craig M. Bobchin <CBobchin@sbcglobal.net > wrote:
>In article <jas5h2hbs4161lt10fngej58ep16l262sr@4ax.com>,
>jameseklein@earthlink.net says...
>> Hello,
>>
>> For weight vs. portability issues and minimum aperture that I can
>> stand, I have decided on an LX200R as my next scope.
>>
>> 1. Can it be focued for best optical performance and then an
>> auxilliary focuser used installed which moves the camera/eyepiece
>> rather than moving the primary. Being a professional optical designer
>> for 30 years, I understand that there is an optimal P to S spacing for
>> best PSF.
>
>Yes it can. In fact the LX200 series comes with a mirror lock knob that
>you use once you have gotten focused. You can then use the standard Zero
>Image shift Microfocuser for fine focusing. This is an electric crayford
>focuser based in JMI's NGF-S model that works through the Autostar.
>
>> 2. Are there after market wedges which provide MAX vibrational damping
>> ?
>
>Again there are several. Meade makes one that they updated when the RCX
>series came out. It wil work with the LX200 series as well.
>
>Ken Milburn makes the Milburn wedge which I had and it is very stable
>and easy to use. Another good after market wedge is the Mettler wedge.
>Search for these on these at Astromart and you might be able to find a
>used one for sale.
>
>> 3. Finally, if there are reasons why this is a stupid or bad choice
>> (sans the $ involved) I would rather hear them now than after I buy.
>
>If you want to get into imaging,there are better systems. Or if you have
>to move the system a lot to observe you might get tired of hauling
>around all the weight. Also if you get a wedge, don't forget
>counterweights. I'd suggest the Losmandy system.
>
>But I liked my LX-200 GPS, but I wanted a better imaging system. Hence
>my pulling th etube and putting it on a G-11.
>
>Craig
>
Is the G-11 a solider and less vibration sensitive mount that the
fork mount of the 10" LX200R ?
Jim
>
>>
>> Sincerely,
>>
>> Jim Klein
>> James E. Klein
>> jameseklein@earthlink.net
>>
>> Engineering Calculations
>> http://www.ecalculations.com
>> ecalculations@ecalculations.com
>> Engineering Calculations is the home of
>> the KDP-2 Optical Design Program
>> for Windows and (soon) MAC OSX
>> Free KDP-2 (DEMO) downloadable!
>> 1-818-507-5706 (Voice and Fax)
>>
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows and (soon) MAC OSX
Free KDP-2 (DEMO) downloadable!
1-818-507-5706 (Voice and Fax)
|
| | | |
Date: 22 Sep 2006 17:30:16
From: Craig M. Bobchin
Subject: Re: Buying a 10" LX200R
|
In article <2ad6h2db2htmuq30ldsmbq2klotqln2lhg@4ax.com >,
jameseklein@earthlink.net says...
> Is the G-11 a solider and less vibration sensitive mount that the
> fork mount of the 10" LX200R ?
Jim,
I think so. It is a GEM which has it's own set of issues to contend with
(Meridian flip being one). If you use a set of vibration suppression
pads under the Meade it damps down much quicker, but the standard Meade
is not bad in the vibration area.
I do know that I like the autostar more than the Losmandy Gemini
system. But the Gemini has a better pointing model and better tracking.
The Losmandy is also more expensive. But I wish I had gone with that
from the beginning. It also allows you to use multiple OTAs unlike the
fork system.
Craig
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Date: 21 Sep 2006 21:08:36
From: Chris L Peterson
Subject: Re: Buying a 10" LX200R
|
On Thu, 21 Sep 2006 20:15:18 GMT, Jim Klein <jameseklein@earthlink.net >
wrote:
>1. Can it be focued for best optical performance and then an
>auxilliary focuser used installed which moves the camera/eyepiece
>rather than moving the primary. Being a professional optical designer
>for 30 years, I understand that there is an optimal P to S spacing for
>best PSF.
While there are aftermarket focusers, I'd pass. The variation in the PSF
over the normal range you will move the mirror in focusing is
insignificant. On the other hand, the effects of moving your equipment
farther out on the mechanical stability of the system are not
insignificant. You may even reach the point where things won't clear the
base.
>2. Are there after market wedges which provide MAX vibrational damping
>?
I think all of the wedges are quite good. From experience I can tell you
that the Meade Superwedge is extremely rigid and doesn't add any
significant vibration to the system. I think it as solid as any. It
isn't the easiest to adjust, however. If you anticipate doing a lot of
realignment it isn't the best choice.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 21 Sep 2006 16:32:22
From: AM
Subject: Re: Buying a 10" LX200R
|
Jim Klein wrote:
> Hello,
>
> For weight vs. portability issues and minimum aperture that I can
> stand, I have decided on an LX200R as my next scope.
It wouldnt hurt my feelings none.
> 1. Can it be focued for best optical performance and then an
> auxilliary focuser used installed which moves the camera/eyepiece
> rather than moving the primary.
Check out JMI, and Van Slyke for very nice after market focusers.
All depends on how much you want to spend. (do you really need
one that will support 12 lbs ?)
> 2. Are there after market wedges which provide MAX vibrational damping
A club member has a Milburn wedge, and I must admit, it is
a hefty well machined piece of gear. He is extremely happy
with it.
> 3. Finally, if there are reasons why this is a stupid or bad choice
> (sans the $ involved) I would rather hear them now than after I buy.
>
> Sincerely,
>
> Jim Klein
Sounds all good to me :)
--
AM
http://sctuser.home.comcast.net
CentOS 4.3 KDE 3.3
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Date: 22 Sep 2006 00:56:35
From: Jim Klein
Subject: Re: Buying a 10" LX200R
|
AM <sctuser@comcast.net > wrote:
>Jim Klein wrote:
>> Hello,
>>
>> For weight vs. portability issues and minimum aperture that I can
>> stand, I have decided on an LX200R as my next scope.
>
>It wouldnt hurt my feelings none.
>
>
>> 1. Can it be focued for best optical performance and then an
>> auxilliary focuser used installed which moves the camera/eyepiece
>> rather than moving the primary.
>
>Check out JMI, and Van Slyke for very nice after market focusers.
>All depends on how much you want to spend. (do you really need
>one that will support 12 lbs ?)
12 LB would support one heck of a cryo-cooler :-)
>
>
>> 2. Are there after market wedges which provide MAX vibrational damping
>
>A club member has a Milburn wedge, and I must admit, it is
>a hefty well machined piece of gear. He is extremely happy
>with it.
>
>
>> 3. Finally, if there are reasons why this is a stupid or bad choice
>> (sans the $ involved) I would rather hear them now than after I buy.
>>
>> Sincerely,
>>
>> Jim Klein
>
>Sounds all good to me :)
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows and (soon) MAC OSX
Free KDP-2 (DEMO) downloadable!
1-818-507-5706 (Voice and Fax)
|
| |
Date: 22 Sep 2006 07:20:25
From: RMOLLISE
Subject: Re: Buying a 10" LX200R
|
Hi Jim:
1. Yes, an "auxiliary focuser" is included in the package. It's focused
via the Autostar. Any spacing problems are minor image wise. With this
or any rear cell Crayford type focuser, you may have to get creative
with adapters if you intend to use focal reducers.
2. Yes. The Mitty wedge is one. The APT Wedge is another.
<http://www.aptastro.com/ >
<http://home.cfl.rr.com/mitty/Firstpage.htm >
3. It sounds as if this is your first serious telescope. The only
caveat is that this is bigger than it looks in the pretty magazine ads.
Yes, even a 10 can be a real hassle for some folks to set up. Have you
looked at one in person? If this might be a problem, consider an
8-inch. You really don't gain anything with a 10 over an 8 if imaging
is to be your main interest, and a 8-inch SCT is still capable of
showing you a hell of a lot from dark skies.
If you have further questions, please feel free to email me direct if
you'd like.
Peace,
Rod Mollise
Author of:
Choosing and Using a Schmidt Cassegrain Telescope
and
The Urban Astronomer's Guide
<http://skywatch.brainiac.com/astroland >
Jim Klein wrote:
> Hello,
>
> For weight vs. portability issues and minimum aperture that I can
> stand, I have decided on an LX200R as my next scope.
>
> 1. Can it be focued for best optical performance and then an
> auxilliary focuser used installed which moves the camera/eyepiece
> rather than moving the primary. Being a professional optical designer
> for 30 years, I understand that there is an optimal P to S spacing for
> best PSF.
>
> 2. Are there after market wedges which provide MAX vibrational damping
> ?
>
> 3. Finally, if there are reasons why this is a stupid or bad choice
> (sans the $ involved) I would rather hear them now than after I buy.
>
> Sincerely,
>
> Jim Klein
> James E. Klein
> jameseklein@earthlink.net
>
> Engineering Calculations
> http://www.ecalculations.com
> ecalculations@ecalculations.com
> Engineering Calculations is the home of
> the KDP-2 Optical Design Program
> for Windows and (soon) MAC OSX
> Free KDP-2 (DEMO) downloadable!
> 1-818-507-5706 (Voice and Fax)
|
| |
Date: 22 Sep 2006 02:31:50
From: atasselli@hotmail.com
Subject: Re: Buying a 10" LX200R
|
Chris L Peterson wrote:
> On Thu, 21 Sep 2006 20:15:18 GMT, Jim Klein <jameseklein@earthlink.net>
> wrote:
>
> >1. Can it be focued for best optical performance and then an
> >auxilliary focuser used installed which moves the camera/eyepiece
> >rather than moving the primary. Being a professional optical designer
> >for 30 years, I understand that there is an optimal P to S spacing for
> >best PSF.
>
> While there are aftermarket focusers, I'd pass. The variation in the PSF
> over the normal range you will move the mirror in focusing is
> insignificant.
Just because you don't seem to appreciate it it doesn't mean it isn't
there I'm afraid.
Andrea T.
|
| | |
Date: 22 Sep 2006 12:58:36
From: Chris L Peterson
Subject: Re: Buying a 10" LX200R
|
On 22 Sep 2006 02:31:50 -0700, "atasselli@hotmail.com"
<atasselli@hotmail.com > wrote:
>Just because you don't seem to appreciate it it doesn't mean it isn't
>there I'm afraid.
I didn't say it isn't there. I said it's insignificant, a fact pretty
well borne out by thousands of observations and images made with SCTs.
I've traced and analyzed SCTs, too. The variation in spot size when you
are focused at infinity and have a backfocus distance within a couple of
inches on either side of optimum is a few tenths of an arcsecond. Very
few observers are using their scope in a way that will make that
important. On the other hand, most SCT mounts are somewhat
underengineered, and adding 4" to the instrument train will almost
certainly introduce instability and resonances that will be obvious to
anyone.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
| |
Date: 22 Sep 2006 00:51:23
From: Hupat Tipo Netscapoetrxcvc
Subject: Re: Buying a 10" LX200R
|
Jim Klein wrote:
> Hello,
>
> For weight vs. portability issues and minimum aperture that I can
> stand, I have decided on an LX200R as my next scope.
>
> 1. Can it be focued for best optical performance and then an
> auxilliary focuser used installed which moves the camera/eyepiece
> rather than moving the primary. Being a professional optical designer
> for 30 years, I understand that there is an optimal P to S spacing for
> best PSF.
which should be somewhere close to where the standard diagonal outs -
?
>
>
> 2. Are there after market wedges which provide MAX vibrational damping
> ?
>
> 3. Finally, if there are reasons why this is a stupid or bad choice
> (sans the $ involved) I would rather hear them now than after I buy.
>
Yea one. A C9.25 is better optically. And a 11" is that much heavier?
... ?
>
> Sincerely,
>
> Jim Klein
> James E. Klein
> jameseklein@earthlink.net
>
> Engineering Calculations
> http://www.ecalculations.com
> ecalculations@ecalculations.com
> Engineering Calculations is the home of
> the KDP-2 Optical Design Program
> for Windows and (soon) MAC OSX
> Free KDP-2 (DEMO) downloadable!
> 1-818-507-5706 (Voice and Fax)
|
| |
Date: 22 Sep 2006 17:05:47
From: atasselli@hotmail.com
Subject: Re: Buying a 10" LX200R
|
Jim Klein wrote:
> "atasselli@hotmail.com" <atasselli@hotmail.com> wrote:
>
> >
> >Chris L Peterson wrote:
> >> On 22 Sep 2006 02:31:50 -0700, "atasselli@hotmail.com"
> >> <atasselli@hotmail.com> wrote:
> >>
> >> >Just because you don't seem to appreciate it it doesn't mean it isn't
> >> >there I'm afraid.
> >>
> >> I didn't say it isn't there. I said it's insignificant, a fact pretty
> >> well borne out by thousands of observations and images made with SCTs.
> >
> >Frankly, I can't believe in the claim of "thousands". There may be
> >"thousands" of observations/images but they came not from 'thousands"
> >of SCTs.
> >
> >>
> >> I've traced and analyzed SCTs, too. The variation in spot size when you
> >> are focused at infinity and have a backfocus distance within a couple of
> >> inches on either side of optimum is a few tenths of an arcsecond.
> >
> >My analysis suggests otherwise, e.g. with variation in focus position
> >of 100mm either side of design backfocus position the variation in
> >correction is up to 1/4 lambda. Never mind what happens to
> >spherochromatism and field correction. I think to remember that Valery
> >once tried to market a kind of chromacorr just for that purpose (i.e.
> >reducing variations of correction with varying focus position).
> >
> >Andrea T.
>
> Certainly the theoretical change in wavefront quality across the field
> of view will be different when focusing a Meade Schmidt Cass or a
> Ritche since in one case the primary is spherical and in the other
> case the primary is hyperbolic.
Except that the LX200R isn't a Ritchie-Cretien but an aspherical
(secondary) SCT, something that should have been long ago.
Andrea T.
|
| | |
Date: 23 Sep 2006 00:21:33
From: Jim Klein
Subject: Re: Buying a 10" LX200R
|
"atasselli@hotmail.com" <atasselli@hotmail.com > wrote:
>
>Jim Klein wrote:
>> "atasselli@hotmail.com" <atasselli@hotmail.com> wrote:
>>
>> >
>> >Chris L Peterson wrote:
>> >> On 22 Sep 2006 02:31:50 -0700, "atasselli@hotmail.com"
>> >> <atasselli@hotmail.com> wrote:
>> >>
>> >> >Just because you don't seem to appreciate it it doesn't mean it isn't
>> >> >there I'm afraid.
>> >>
>> >> I didn't say it isn't there. I said it's insignificant, a fact pretty
>> >> well borne out by thousands of observations and images made with SCTs.
>> >
>> >Frankly, I can't believe in the claim of "thousands". There may be
>> >"thousands" of observations/images but they came not from 'thousands"
>> >of SCTs.
>> >
>> >>
>> >> I've traced and analyzed SCTs, too. The variation in spot size when you
>> >> are focused at infinity and have a backfocus distance within a couple of
>> >> inches on either side of optimum is a few tenths of an arcsecond.
>> >
>> >My analysis suggests otherwise, e.g. with variation in focus position
>> >of 100mm either side of design backfocus position the variation in
>> >correction is up to 1/4 lambda. Never mind what happens to
>> >spherochromatism and field correction. I think to remember that Valery
>> >once tried to market a kind of chromacorr just for that purpose (i.e.
>> >reducing variations of correction with varying focus position).
>> >
>> >Andrea T.
>>
>> Certainly the theoretical change in wavefront quality across the field
>> of view will be different when focusing a Meade Schmidt Cass or a
>> Ritche since in one case the primary is spherical and in the other
>> case the primary is hyperbolic.
>
>Except that the LX200R isn't a Ritchie-Cretien but an aspherical
>(secondary) SCT, something that should have been long ago.
Thanks, I will look at the Ritchies then. My mis-understanding.
>
>Andrea T.
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows and (soon) MAC OSX
Free KDP-2 (DEMO) downloadable!
1-818-507-5706 (Voice and Fax)
|
| |
Date: 22 Sep 2006 14:37:58
From: atasselli@hotmail.com
Subject: Re: Buying a 10" LX200R
|
Chris L Peterson wrote:
> On 22 Sep 2006 02:31:50 -0700, "atasselli@hotmail.com"
> <atasselli@hotmail.com> wrote:
>
> >Just because you don't seem to appreciate it it doesn't mean it isn't
> >there I'm afraid.
>
> I didn't say it isn't there. I said it's insignificant, a fact pretty
> well borne out by thousands of observations and images made with SCTs.
Frankly, I can't believe in the claim of "thousands". There may be
"thousands" of observations/images but they came not from 'thousands"
of SCTs.
>
> I've traced and analyzed SCTs, too. The variation in spot size when you
> are focused at infinity and have a backfocus distance within a couple of
> inches on either side of optimum is a few tenths of an arcsecond.
My analysis suggests otherwise, e.g. with variation in focus position
of 100mm either side of design backfocus position the variation in
correction is up to 1/4 lambda. Never mind what happens to
spherochromatism and field correction. I think to remember that Valery
once tried to market a kind of chromacorr just for that purpose (i.e.
reducing variations of correction with varying focus position).
Andrea T.
|
| | |
Date: 22 Sep 2006 23:07:41
From: Jim Klein
Subject: Re: Buying a 10" LX200R
|
"atasselli@hotmail.com" <atasselli@hotmail.com > wrote:
>
>Chris L Peterson wrote:
>> On 22 Sep 2006 02:31:50 -0700, "atasselli@hotmail.com"
>> <atasselli@hotmail.com> wrote:
>>
>> >Just because you don't seem to appreciate it it doesn't mean it isn't
>> >there I'm afraid.
>>
>> I didn't say it isn't there. I said it's insignificant, a fact pretty
>> well borne out by thousands of observations and images made with SCTs.
>
>Frankly, I can't believe in the claim of "thousands". There may be
>"thousands" of observations/images but they came not from 'thousands"
>of SCTs.
>
>>
>> I've traced and analyzed SCTs, too. The variation in spot size when you
>> are focused at infinity and have a backfocus distance within a couple of
>> inches on either side of optimum is a few tenths of an arcsecond.
>
>My analysis suggests otherwise, e.g. with variation in focus position
>of 100mm either side of design backfocus position the variation in
>correction is up to 1/4 lambda. Never mind what happens to
>spherochromatism and field correction. I think to remember that Valery
>once tried to market a kind of chromacorr just for that purpose (i.e.
>reducing variations of correction with varying focus position).
>
>Andrea T.
Certainly the theoretical change in wavefront quality across the field
of view will be different when focusing a Meade Schmidt Cass or a
Ritche since in one case the primary is spherical and in the other
case the primary is hyperbolic.
I'm looking to buy the LX200R 10". The weight I'm somewhat familiar
with since I owned a 10" Meade in 1990. My back is 16 years older but
I have a strong wife so the weight should be OK.
As a side note, anyone here in amateur astronomy is welcome to a free
copy of my optical design program. I certainly whould never charge
anyone who is an amateur astromoner. I just charge folks in the
commercial optics business.
The free version of my code is at the web site below and the non-free
version is downloadable after which you just send me an email telling
me you are an amateur astronomer and I'll email you PKZIP password.
My program may not be as easy to use as ZEMAX but it won't cost you
thousands of dollars and I answer all email questions it what I hope
is a freindly manner.
Sincerely,
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows and (soon) MAC OSX
Free KDP-2 (DEMO) downloadable!
1-818-507-5706 (Voice and Fax)
|
|
