"siteching" a Celestron CI-700?


Dave Lane
 

Has anyone converted the drives of a CI-700 to the sitech system? If so, can you provide some details on what was involved mechanically and what motors were used?

--- Dave


Joshua Hufford
 

Hi Dave, it can be done but it isn't easy. To be honest, unless you already have a CI-700 or come across one dirt cheap, I think a better way to go is to use a G-11 and make use of the Gemini motors. My friend Anthony helped me convert mine several years ago, but it took a lot of machine work to make brackets to hold the motors, and a lot of tweaking to make it work well. The mount did image well but I did eventually replaced it with a MI-250, although we still use the CI-700 from time to time for visual observing. One major problem is the worm housing on the CI-700 isn't designed very well and it is pretty much impossible to get rid of the backlash without causing binding, with mine it usually takes 20-30 seconds of tracking to take up the slack if it is slewed in the opposite direction, obviously this isn't a problem when you are only using a tracking motor to drive the RA. Also the clutch design on the CI-700 leaves a lot to be desired. 

The mount does have some decent quality gears, although the PE is a bit large it is smooth and easy to guide out, I produced some great images with my SiTech converted CI-700. 

Here are a few pictures of it, 



Josh

On Sun, Aug 8, 2021 at 11:32 AM Dave Lane <dave@...> wrote:
Has anyone converted the drives of a CI-700 to the sitech system? If so,
can you provide some details on what was involved mechanically and what
motors were used?

--- Dave







James Roe
 

Dave, I did it and it wasn't too hard in one sense.  I attached timing belt pulleys to the worm shafts and drove them via a timing belt and smaller pulleys in the servo motors (about5:1).  I had some very crude brackets made out of wood.  These days I would do something with a 3D printer.

As Joshua mentioned, the worm design really sucks, basically not adjustable.  But I made it work and for many years  I ran a scripted variable star program sometimes hitting 50 or more targets a night.

Jim Roe

On Sun, Aug 8, 2021, 11:32 AM Dave Lane <dave@...> wrote:
Has anyone converted the drives of a CI-700 to the sitech system? If so,
can you provide some details on what was involved mechanically and what
motors were used?

--- Dave







Dave Lane
 

Thanks Joshua, for the detailed reply and pictures. I originally thought it might have been built by Losmandy, but my googling would indicate it was Celestron's first attempt after reselling/rebranding the G11. The mount is free to me - a fellow is giving me a long unused C-700 + C14 from the mid 90s. I expect it really is not beefy enough for a C14, except for visual use. I'm also getting a couple of what looks like un-used Meade Pictor CCD cameras :-).

Dave

ps. I see you have one of the rare Kendrick Premier Power Controllers - that was my design. I never did get one myself. He did not sell many of them based on the royalties that I received!


Dave Lane
 

Thanks James - I'll see what is possible once I get the system.


Joshua Hufford
 

Well, free is certainly good! 

I would certainly try not to image with the C14 on this mount, I think that would really be pushing it. 

The other poor design of this mount is the clutch system, the tighter you make the clutch the more friction there is to movement of each axis and more load on each motor. From what I understand the clutches are actually designed to slip when you want to move the scope to a new target, then the scope begins to track again when you stop moving. 

Honestly, if the drives still work on the mount, I would probably just use it for visual observing with the stock drive, this mount is not the best candidate for converting to GOTO. 

BTW I believe I have mounting brackets for encoders if you would be interested, the encoders have been repurposed, but I still have the brackets. 

It is neat that you designed the Kendrick Dew controller, I think it is a fantastic unit. I actually have 2 of them, both bought used. One of them has a failure, either the temperature or humidity doesn't sense properly (don't remember which one now). My friend Anthony uses it and just sets the heat percentage manually. The other one I have still works perfectly. I always thought this was a great design, great job! I don't think they are sold any more? 

Josh

On Wed, Aug 11, 2021 at 7:26 AM Dave Lane <dave@...> wrote:
Thanks Joshua, for the detailed reply and pictures. I originally thought it might have been built by Losmandy, but my googling would indicate it was Celestron's first attempt after reselling/rebranding the G11. The mount is free to me - a fellow is giving me a long unused C-700 + C14 from the mid 90s. I expect it really is not beefy enough for a C14, except for visual use. I'm also getting a couple of what looks like un-used Meade Pictor CCD cameras :-).

Dave

ps. I see you have one of the rare Kendrick Premier Power Controllers - that was my design. I never did get one myself. He did not sell many of them based on the royalties that I received!


jervisbayastro
 

Hi Dave,

I have a CI-700 waiting for a goto conversion but lack of parts and machining skills has stalled it for now. My research took me to a few sites including Cloudy Nights and Jim Fusco's CI-700 upgrade https://astromart.com/reviews-and-articles/reviews/telescopes/show/ci-700-hercules.  Unfortunately the link to his notes etc no longer seems to be accessible but at some point in the past I was able to see what he. Consequently I acquired the NTA-4860 needle roller bearings he used to replace the existing thrust surfaces to improve the rotation of the RA and Dec. I may have some other references to CI-700 mods if you're interested.

Regards,
Col Shepherd


Dave Lane
 

Col,

I found the linked website on the internet archive (an excellent site for finding old content back as far as the mid 90s!).

See: https://web.archive.org/web/20041125031511/http://www.geocities.com/jgfusco3/CI-700Hercules.html

--- Dave


Dave Lane
 

I take that back - it looks like the actually content pages were not archived. :-(


jervisbayastro
 

Dave,
I went down that same rabbit hole but can't find the end now. Digging back through my CI-700 'database" I have found other CI-700 related info I've collected plus there could be a copy of the original "Hercules" page files and photos. I haven't worked out how to reconstruct it yet but there appear to be some photos which may be of use. I'll have a dig through it.

In my original reply I conflated what I thought I remembered of that site with this one regarding the thrust bearing mod. 
http://www.skydude.me/ci700mods.html

Not sure if this page is relevant.
https://www.cloudynights.com/topic/374428-why-am-i-wrong-synscan-upgrade-on-a-ci-700/page-2

A CI-700 OnStep conversion in french, but the photos don't need translation :)
https://www.webastro.net/forums/topic/168576-onstep-celestron-ci700/

I think the attachment is from the CN archive.