Re: [ap-gto] Re: 20" RC


Nov 19, 2003

 


----------------------------

#9126 Nov 19, 2003

Hello,

I am looking for sites that have AP1200's and 20" RC's. I am

curious why the ME which has a posted aprox. weight limit of 125 lbs

is the mount of choice for the 20" RC? (other than robotic uses).

The AP1200GTO lists a weight limit of 140lbs. I have a chance to

purchase a used 20" RC truss tube and I have an AP1200GTO in a back

yard observatory and the scope weighs 135lbs and there will be about

15lbs more stuff (CCD...AO7..etc) and I love my AP1200. I am hoping

with proper balancing that this mount would be able to handle the

load for CCD imaging. I remember Brad having a pic awhile back with

the AP12000 with a 20" tube RC. I have scanned past messages and

have found plenty of 16" RC's and AP1200's. And at the RC site they

list the AP1200 for up to the 16" RC and the ME for upto the 20".

Am I being to hopefull that I will be able to keep the AP1200 with

this setup. Is anyone doing CCD imaging with the AP1200 with a 150lb

load??



Thanks for the help..



Ken



----------------------------

#9129 Nov 20, 2003

I am looking for sites that have AP1200's and 20" RC's.



Hi Ken,



I'm not sure that there are that many 20" RC's out there - only

the lucky! I own the AP1200 mount that Brad used with his 20" RC, and

although it has a somewhat smaller RC on it now, it still performs

very well.



Interestingly, if you look at the Software Bisque web site they

don't recommend putting a 20" on the ME either. In my opinion,

properly balanced - either mount will carry a big OTA like that. Your

AP1200 should do just fine.



Kevin Walsh



----------------------------

#9130 Nov 20, 2003

Hi Ken,



I can't vouch for a 20" but I've got a monster 16" Aries on an AP1200.

I've not weighed it, but it was a major effort lifting it onto the

mount, I'd estimate it at something along the lines of 100+ lbs.

On this, I've piggybacked an AP130EDT refractor. You can see the rig

at:

www.soleburymountain.com

www.soleburymountain.com/Aries16



On this, I use an SBIG ST10-XME, AO-7 and FLI filter wheel.



This load is pushing the limits of the setup. In cold weather, the

servo drives groan, even driving at 600x slewing. This is with

everything very well balanced with a slight positive load to keep the

gears loaded.



I would NOT want to track this rig without the AO-7. The system

definitely stuggles to keep from "ringing" when bumped, though it does

dampen quickly. But you can really tell the weight is loading it. You

can't see it in the pictures, but I'm using 5 of the big

counterweights and an extended DEC axle.



I'm sure AP can comment on the absolute limits for the 1200. But from

a practical perspective, I've got to say you'll be pushing it with a

scope that's even heavier than the one I'm using!



Best of luck,

Ted

--- In ap-gto@yahoogroups.com, "Ken Crawford" dcoc1@i...> wrote:

> Hello,

> I am looking for sites that have AP1200's and 20" RC's. I am

> curious why the ME which has a posted aprox. weight limit of 125 lbs

> is the mount of choice for the 20" RC? (other than robotic uses).

> The AP1200GTO lists a weight limit of 140lbs. I have a chance to

> purchase a used 20" RC truss tube and I have an AP1200GTO in a back

> yard observatory and the scope weighs 135lbs and there will be about

> 15lbs more stuff (CCD...AO7..etc) and I love my AP1200. I am hoping

> with proper balancing that this mount would be able to handle the

> load for CCD imaging. I remember Brad having a pic awhile back with

> the AP12000 with a 20" tube RC. I have scanned past messages and

> have found plenty of 16" RC's and AP1200's. And at the RC site they

> list the AP1200 for up to the 16" RC and the ME for upto the 20".

> Am I being to hopefull that I will be able to keep the AP1200 with

> this setup. Is anyone doing CCD imaging with the AP1200 with a 150lb

> load??

>

> Thanks for the help..

>

> Ken



----------------------------

#9131 Nov 20, 2003

Hi,



The visitor telescope at the Kitt Peak amateur telescope is an RCOS

20" RC on a paramount. Imaging is with ST10+Ao7. It works pretty well.



www.trivalleystargazers.org/gert/kitt_peak/visitor/visitor.html



Clear Skies,



Gert

--- In ap-gto@yahoogroups.com, "kkhhww65" kw@d...> wrote:

> > I am looking for sites that have AP1200's and 20" RC's.

>

...

> Interestingly, if you look at the Software Bisque web site they

> don't recommend putting a 20" on the ME either. In my opinion,

> properly balanced - either mount will carry a big OTA like that. Your

> AP1200 should do just fine.

>

> Kevin Walsh



----------------------------

#9132 Nov 20, 2003

Thanks for the replies...



I will give it a shot... I have to order the longer dovetail plate

and the longer weight shaft...



Ken Crawford

--- In ap-gto@yahoogroups.com, "Ted Inoue" ted@s...> wrote:

> Hi Ken,

>

> I can't vouch for a 20" but I've got a monster 16" Aries on an

AP1200.

> I've not weighed it, but it was a major effort lifting it onto the

> mount, I'd estimate it at something along the lines of 100+ lbs.

> On this, I've piggybacked an AP130EDT refractor. You can see the

rig

> at:

> www.soleburymountain.com

> www.soleburymountain.com/Aries16

>

> On this, I use an SBIG ST10-XME, AO-7 and FLI filter wheel.

>

> This load is pushing the limits of the setup. In cold weather, the

> servo drives groan, even driving at 600x slewing. This is with

> everything very well balanced with a slight positive load to keep

the

> gears loaded.

>

> I would NOT want to track this rig without the AO-7. The system

> definitely stuggles to keep from "ringing" when bumped, though it

does

> dampen quickly. But you can really tell the weight is loading it.

You

> can't see it in the pictures, but I'm using 5 of the big

> counterweights and an extended DEC axle.

>

> I'm sure AP can comment on the absolute limits for the 1200. But

from

> a practical perspective, I've got to say you'll be pushing it with

a

> scope that's even heavier than the one I'm using!

>

> Best of luck,

> Ted

>

> --- In ap-gto@yahoogroups.com, "Ken Crawford" dcoc1@i...> wrote:

> > Hello,

> > I am looking for sites that have AP1200's and 20" RC's. I am

> > curious why the ME which has a posted aprox. weight limit of 125

lbs

> > is the mount of choice for the 20" RC? (other than robotic

uses).

> > The AP1200GTO lists a weight limit of 140lbs. I have a chance

to

> > purchase a used 20" RC truss tube and I have an AP1200GTO in a

back

> > yard observatory and the scope weighs 135lbs and there will be

about

> > 15lbs more stuff (CCD...AO7..etc) and I love my AP1200. I am

hoping

> > with proper balancing that this mount would be able to handle

the

> > load for CCD imaging. I remember Brad having a pic awhile back

with

> > the AP12000 with a 20" tube RC. I have scanned past messages

and

> > have found plenty of 16" RC's and AP1200's. And at the RC site

they

> > list the AP1200 for up to the 16" RC and the ME for upto the

20".

> > Am I being to hopefull that I will be able to keep the AP1200

with

> > this setup. Is anyone doing CCD imaging with the AP1200 with a

150lb

> > load??

> >

> > Thanks for the help..

> >

> > Ken







----------------------------

#9137 Nov 21, 2003

At 06:06 PM 11/20/2003 +0000, kkhhww65 wrote: > > I am looking for sites that have AP1200's and 20" RC's.

>

>Hi Ken,

>

> I'm not sure that there are that many 20" RC's out there - only

>the lucky! I own the AP1200 mount that Brad used with his 20" RC, and

>although it has a somewhat smaller RC on it now, it still performs

>very well.

>

> Interestingly, if you look at the Software Bisque web site they

>don't recommend putting a 20" on the ME either. In my opinion,

>properly balanced - either mount will carry a big OTA like that. Your

>AP1200 should do just fine.



The big problem is wind ...

If you put a 20" RC up on these mounts, you may want a dome to give you

some wind protection.



Dave



----------------------------

#9299 Dec 27, 2003

Hello group,



After carefull balancing, Tpoint models, learning to use the AO7,

and the clouds breaking last night I was able to image my first LRGB

with my new 20" RC. All though under mounted for the weight, the

AP1200GTO is working like a champ with great pointing (RMS of under

10). I do have to use the AO7 for tracking as any little bump or

breeze will smear the image at .34 arc/pix when unbinned. Even

though it is not a perfect image taken though not great seeing, I am

very excited about the potential and I am excited about learning to

be more proficient with it.



www.rdelsol.com/FirstPage/M82_RC20.htm



Thanks for looking,



Ken Crawford



----------------------------

#9300 Dec 27, 2003

Wow, spectacular Ken. Extremely nice detail.

Looking to put my 12.5 on my repaired 1200. Even built a new

observatory for it.



Michael Cole

UrbanImager Astrophotography website

home.earthlink.net/~urbanimager/index.htm







Ken Crawford wrote:

>Hello group,

>

>After carefull balancing, Tpoint models, learning to use the AO7,

>and the clouds breaking last night I was able to image my first LRGB

>with my new 20" RC. All though under mounted for the weight, the

>AP1200GTO is working like a champ with great pointing (RMS of under

>10). I do have to use the AO7 for tracking as any little bump or

>breeze will smear the image at .34 arc/pix when unbinned. Even

>though it is not a perfect image taken though not great seeing, I am

>very excited about the potential and I am excited about learning to

>be more proficient with it.

>

>www.rdelsol.com/FirstPage/M82_RC20.htm

>

>Thanks for looking,

>

>Ken Crawford

>

>

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>

>



--

Michael Cole

UrbanImager Astrophotography website

home.earthlink.net/~urbanimager/index.htm



----------------------------

#15521 Jul 21, 2006

--- In ap-gto@yahoogroups.com, "ocular21" rbissinger@...> wrote: >

> Reviewing some previous threads on this list as well as on other

lists > still leaves me wondering if a 20" truss RC could be managed by an

> AP1200GTO. Would appreciate hearing from anyone with direct

experience > with such a setup, thanks.





I'm using a home made 18" f/12.6 (F=5700mm) truss tube classical

cassegrain on my older AP1200GTO and am getting fine results so long

as the wind is light (~5mph) or non-existent. The telescope weighs

about 120# with full instrument load on it, possibly a tad less.



I believe that a 20" Truss tube RC such as the RCOS one would work

about as well on the mount, but both are basically approaching the

limit.



here's a recent shot from my 18"/ap1200gto:



www.narrowbandimaging.com/hh555_mk1sn2_cm10_geg_CSs2hao3_page.h

tm



I am getting stars in the low 2s this week with the good seeing I've

been experiencing and that is for 30 minute subexposures and guiding

is conventional (ie non-AO7) guiding.



One person mentioned to me that my star diameters were smaller and my

nebula better resolved than images of the same object taken with a

20" RCOS in Mayhill, NM and a 16" RCOS at Kitt Peak. It is too bad

those images were shot in RGB or LRGB because it make them a bit

harder to compare since narrowband filters greatly attenuate star

intensity so they have stars in their images that do not appear in

mine. Still FWHMs of stars and nebular resolution can still be

compared though.



Obviously seeing usually is the deciding factor and I'd like to see

the performance of the respective systems in side by side test at the

same time in the same location. But with the limited data I have so

far I think I am 'in the hunt' so to speak.



By the way my mirror has a chip out of it about 4" square due to an

unfortunate accident a year and a half ago, but it seems to be

working well nonetheless.



I am happy with the AP1200s ability to handle my load though.







>







----------------------------

#15844 Sep 11, 2006

In a message dated 9/11/2006 5:13:20 PM Central Daylight Time, waltc@...

writes:



> Hi folks,

>

> Has anyone succesfully run a 20" RC OTA on an AP-1200?

>



If it's a light weight carbon fiber scope, I believe so. How much does yours

weigh?



Roland Christen





[Non-text portions of this message have been removed]



----------------------------

#15847 Sep 11, 2006

In a message dated 9/11/2006 6:17:35 PM Central Daylight Time, waltc@...

writes:



> Uh, well, I don't actually HAVE a 20" RC OTA yet. But that's just a

> minor detail. :-)

>

> A friend has a set of Paul Jones RC optics and we are looking at

> buying or building an OTA around them. What would you think our

> weight limit ought to be for an OTA with this kind of geometry Roland?

>



I would make it a truss system to keep the weight down.



Roland Christen





[Non-text portions of this message have been removed]



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