Re: AP1100, Berlebach Planet, mounting CP4


ap@CaptivePhotons.com
 

As a follow on question with a Berlebach planet.

I received the mounting ring from Berlebach, and it emphasized how large the base of the AP1100 will be in comparison to this tripod.

I do not plan to have more than about 45 pounds of OTA, and counterweights of course. 

Does anyone with a similar setup have any kind of idea where the center of gravity is for that kind of setup?  Specifically how far off center?  

I typically image with the legs retracted fully for stability, and legs at closest are 9.5" (between legs) and 17" (at a single leg) from center.  I prefer to image with the single leg south not north, this provides a LOT more clearance (at least on my MyT) near zenith to avoid leg crashes.  But when I looked at that 9.5" it made me worry, this is a larger mount and probably different CG.

I found the Dimension Calculator spreadsheet, clearly aimed at clearance not load.  But I think (emphasis on think) that the point in the first image labeled as offset B, represents the BALANCED CG, basically at the intersection with the DEC axis.  

But what I am worried about is the unbalanced CG -- the point at which I have loaded 50# or so of counterweights and have yet to attach the OTA.  I.e. the situation why everyone says "put the single leg under the counterweight shaft".  Which is good advice I hope to not have to take so I don't hit the legs with my imaging train.

This all works fine on the MyT, it is quite stable.  But worried -- am I in for a rude surprise with the larger AP1100 (with 45# load)?  Yes, this is easy to figure out once I get it -- but if I need a new tripod/pier I'd like to get it on order now.

Anyone know where the CG is going to land?   And yes, I realize it's latitude dependent (I'm at 26d) but any real world experience welcome.

Linwood

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