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Tube Rings for 12" LX200R - Question

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#1 ASTERON

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Posted 27 January 2013 - 12:18 PM

Just got a DM6 (Sans Tripod) for mounting my 12" LX200R Deforked OTA.
Up to now I've been mounting the OTA on an Atlas EQ6 by using a 4" Losmandy D-type Dovetail Attached to the OTA by Radius Blocks. This worked fine. Looking at the way the OTA is mounted on the DM-6 (OTA is hanging sideways from the Saddle- so all the OTA weight of close to 40 pounds is hanging on the Radius Blocks all the time) I began to worry that this is not realy safe because all those 40 pounds are being held by 4 screws going into the reinforcing rings to which the two radius blocks are attached.

So my questions are:

1) Is the metal of the OTA where the radius blocks are connected by screws sturdy enough to securely hold the OTA in all positions (especially since the tube weight will create a permanent moment on the four screws holding the radius blockes attached to the OTA) ?

2) Has anybody here had any experience with mounting a 12" LX200R OTA on a Losmandy D-type dovetail and Radius Blocks ? Is this type of mounting strong enough to support the weight of the tube hanging sideways (as it would be when mounted on a DM-6)?

3) Does anybody know if there are any commercially made mounting rings specifically made for the dimensions of the 12"LX200R ? Are there any strong rings made that match the radius of this OTA ?

P.S.- I am familiar with the Parallax rings (13.6") but they are made from die-cast Aluminum. I am not realy sure how strong they are ?

Any Help and comments will be greatly appreciated !

Thanks for your :help:

#2 Bill Barlow

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Posted 27 January 2013 - 10:47 PM

I own a Meade 12" ACF OTA and have the Losmandy mounting blocks and rail attached to the scope. I also mount it in a vertical position on a UA Unistar altaz mount. I have had no problems whatsoever with using the Losmandy mounting hardware with this setup for the past few years. I periodically check the four screws that bolt into the radius blocks, but they are always tight. As long as your DM6 mount can handle the 40 pound weight, you should be okay.

Bill

#3 Christopher Erickson

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Posted 27 January 2013 - 10:49 PM

I have radius blocks and Losmandy-style dovetail bars on top and bottom of my 16" LX200 OTA.

They are very strong and rigid and mount very-securely to the threaded holes on the OTA.

I use the bottom bar for counterweights, piggyback OTA's, cameras and such.

I use the top bar for piggyback OTA's and a threaded eye bolt that helps me take apart the scope so I can set it up and take it down by myself in the field. The weight on the eye bolt, dovetail bar, radius blocks and four mounting screws is about 135 pounds.

I have also used the bottom dovetail bar for mounting the 75 pound OTA on various big GEM mounts, like the Astro-Physics 1200GTO. Carries it with no problem at all.

A 12" OTA would be a piece of cake.

#4 ASTERON

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Posted 28 January 2013 - 03:02 AM

Bill and Chris,
Thanks, that's reassuring. I hope the DM6 holds the OTA well. I am still looking for a real sturdy tripod for the DM6.
I've heard good things about the Rob Miller Tri36H
But right now he is not available for doing business as he is organizing a new company.
I will try to home build a good wood tripod until I can buy something decent.
At least now I can do so with some peace of mind.
Thank you for your comments.






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