Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1952
Loc: Boechout, Belgium
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This mount is not a first time mount.
It should be well planned to have this one completely in balance.
Here again this one is build completely out of plywood except for the RA weels, and a small polaraxis.
This mount has a very low COG.
Bearings :
Decl : Teflon/formica
RA : Ball bearings
Usage :
1- Small to medium telescopes.
2- Reflector (mostly Newtontelescopes).
3- If well made transportable in a regular car.
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Chris
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Joe Cipriano
Entropy Personified
Reged: 09/03/05
Posts: 3830
Loc: Uh... anyone have a GPS?
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Dug this up on the web...
Split ring with truss-tube Newt
Split ring mount broken down
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In the Land of Eternal Light Pollution & Great Pizza (Chicago)
SN-6, ED80, WO 66SD
Meade 208xt, SBIG ST-4
D70 (modified)
CGE (way modified)
A Wife who understands (unmodified)
Some other stuff...
I may not have gone where I intended to go, but I think I have ended up where I needed to be.
Douglas Adams
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rmcpb
Carpal Tunnel
Reged: 11/16/04
Posts: 1566
Loc: Blue Mountains, NSW, Australia
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Chris,
Do you do these diagrams in Google Sketchup? They are impressive to say the least.
The split ring mount is what I want to put into my observatory when I finish it. Then I could take the scopes out and use them as dobs or on the equatorial platform when I am at another site. Best of all worlds 
Cheers
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Rob
8" & 13" Dobs
Equatorial Platform
Couple of Panoptics and a handful of BO/TMBs
9x60 binocs
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Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1952
Loc: Boechout, Belgium
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Nope, not Google Skechtup. I've tried it a while ago, but I'm afraid Sketchup is not capable of doing this kind of detailed work. But like I said it's a while ago, maybe sketchup has more 'tools' and 'utilities' these days.
I do all my drawing in Inventor 2008 (Autodesk)
Clever to have a scope with these two different mounts.
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Chris
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Denis
sage
Reged: 12/24/05
Posts: 225
Loc: Rennes, France
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Another thing to think if you make a split ring mount is the need of a rotative OTA, so you can have the eyepiece always at the good position.
You'll also need to compute the COG with precision and make a very light secondary cage to keep the split ring in acceptable range of weight and size.
Three examples :
http://www.reto.fr/telescope
http://www.reto.fr/t350
http://www.reto.fr/modif
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Canon 10x42 IS binoculars.
Meade sc 4" on homemade fork equatorial mount.
homemade 10" an 14" dobsonian
Nikon photogear.
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Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1952
Loc: Boechout, Belgium
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Thanks Denis.. 
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Chris
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lukasik
scholastic sledgehammer
Reged: 10/11/05
Posts: 875
Loc: Lawrenceville, Georgia
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Hi Folks,
Here's another split ring. The rotating OTA is a must with this setup.
Regards,
Bob
Edited by lukasik (08/05/08 10:07 AM)
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Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1952
Loc: Boechout, Belgium
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Hi Bob,
That's no splitring imo.
I'd call this one a reversed horsshoe.
Nice mount btw...
Not yet stumbled over the wires...??.. 
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Chris
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Old Dinosaur
scholastic sledgehammer
Reged: 05/08/07
Posts: 839
Loc: Out in the sagebrush
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I like newts and I like them carried on a split ring.
Some great examples shown above.
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WRS Observatory
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lukasik
scholastic sledgehammer
Reged: 10/11/05
Posts: 875
Loc: Lawrenceville, Georgia
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Hi Chris,
I'll follow your lead about the name. As far as the wires: one freezing cold night I walked away with the handpad in the pocket of my coveralls. Of course it ripped the connector off of the main circuit board to protect the rj-11 on the handpad. 
Cheers,
Bob
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Joe Cipriano
Entropy Personified
Reged: 09/03/05
Posts: 3830
Loc: Uh... anyone have a GPS?
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Link to EP position discussion
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In the Land of Eternal Light Pollution & Great Pizza (Chicago)
SN-6, ED80, WO 66SD
Meade 208xt, SBIG ST-4
D70 (modified)
CGE (way modified)
A Wife who understands (unmodified)
Some other stuff...
I may not have gone where I intended to go, but I think I have ended up where I needed to be.
Douglas Adams
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Kobayashi
sage
Reged: 07/10/08
Posts: 291
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Quote:
This mount has a very low COG.
The OTA needs to have a very log COG as well, for this design to work. Is this mount designed around a specific existing OTA? I don't think I've seen a solid tube Newtonian with the COG so far down.
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-- Ken Kobayashi
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Chriske
Kijkerbouw Urania
Reged: 08/15/04
Posts: 1952
Loc: Boechout, Belgium
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Correct... But I have hidden a few lead blocks around the mirror to lower the COG in this drawing....
Just kidding.... indeed this mount requires a truss scope.
I will correct it later.
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Chris
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Houdini
sage
Reged: 07/13/07
Posts: 392
Loc: Europe
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I've seen a couple of 200 mm f/6 scopes with solid tubes on split rings.
They used a counterweight (5 to 10 kg of lead, not sure) below the mirror cell that could easily be removed for transport.
Robert
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16" f/4.9 motorized alt-az, 25" f/5 Dobson, 43" f/4 alt-az in construction
Mirror Edge Support Calculator
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Old Dinosaur
scholastic sledgehammer
Reged: 05/08/07
Posts: 839
Loc: Out in the sagebrush
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I've got about 60#s of lead, cast iron and steel below the mirror to get the GOG where I need it. And sometimes have to add more for heavy cameras, etc.
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WRS Observatory
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Dick Parker
super member
Reged: 08/17/07
Posts: 143
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You are on to something really neat.
For further information, you will find this design mount written up in Telescope Making magazine, issue 27, spring 1986, page 32, by Joel Pearson. In the article, aside from describing construction details, Joel mentions the need for an eccentric weight to offset the eyepiece and any other non-symmetric objects (finders) that may be attached to the scope.
Attached is a photo of a version of Joel's mount that I built in 1998 for a 12 inch telescope. I took this telescope and mount to Stellafane in 1998. Two years later there were several similar mounts entered which can be viewed on the convention 2000 results.
The design works very well and the axes being equatorial is a tremendous convenience. As with any equatorial system, the eyepiece can get to difficult to access places. To overcome this, I made a rotating nose to place the eyepiece where it is comfortable. To overcome the collimation difficulties, I used threaded rods from the mirror cell up to the front of the tube near the eyepiece so I could easily recollimate when I rotated the tube. That idea was published in Sky&Tel in the Sept issue of that year under "top 10 ideas for the year"
Dick Parker
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