Balancing a Piggybacked ST80

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Balancing an Orion ST80 Guidescope

The Issue - Mounting an Orion ST80 as a "Guidescope" on my 12" LX200 Classic.  This is how I got it to work.
 

The result - ST80 offset on top, new modified weights underneath and almost perfect balance.

 

Having read many message posts to groups and from websites, I knew an LX200 Classic needs to be properly balanced. One detail of that is that the East Fork, the one opposite the Dec Motor, needs additional weight to preload the RA drive. The MAPUG Archive had a specific quote, I believe from Doc G, that says "... judicious placement of accessories to achieve balance with minimum added weights.." I took this to heart and....

 

So that should preload the RA Drive just fine. However the ST80 is relatively heavy and completely upset the minimal balance I had previously achieved. Balancing was in order and I was prodded by a new thread on the subject from the LX200 Yahoo Group to do it .

 
To make the weight adjustable and stable, I used what is known as "Shelf Standard".

 
How I did it... Details below..

The weights I acquired a couple years ago at a Yard Sale. No body knew what they were, so they were $5

They are tapped on one side and have a matching 10-24 stud on the other, so they all screw to each other. These are attached with a single 10-24 by 1" bolt thru a widened slot of the Shelf Standard. A large effective flat surface is created, making these very stable.

The whole contraption is mounted to my mounting rail. It is a two piece "Miter Track", from Vermont Tool, and epoxied together. To hold the weight bar, from the miter track down, is a 1/4-20 x 1" "T Bolt",  (3) 1/4" flat washers, the Shelf Standard, a 1/4" washer, and a 1/4-20 Wingnut.

 
SOME NOTES
You might note that the mounting rail on the top is a different design. This was a mistake, as way back when I made them, I thought they were screwed to the smaller screws on the OTA. I need to remake them longer to actually fit and be more stable. They work perfectly for me, but I am not an Imager.  Outriggers would go a long way to solving that issue.

Also, using the "real" T Bolts instead of the cheapos I bought because I couldn't find the originals will help too.

 

Looks Like I was done just in time

UPDATED
Today I remounted the ST80 in an effort to remove around a quarter of a degree of flop when pointing east, then west. Below are the images of what I did. Please compare to the above.
 
First I mount the Orion Rings to the 1 1/2 x 1/8" Aluminum. Note the holes at each end of the bar are angled, as these are to be mounted uncurved.

 
Tighten it all down and Presto! It curves itself perfectly.

What do you see above??

3 Point ORION Mounting rings

3/4" "Mitre Track" with inner T Bolt rail from Vermont Tool. These were two part epoxied, clamped and dried overnight. These were later drilled thru and bolted every 4-6" to 1/8" flatbars, with tiny slotted countersunk screws with little nylon nuts underneath. This is why the fender washers are used to stand off the rails so those nuts do not hit OTA.

1" T-Bolts (also from Vermont Tool). 1/4" nuts and washers. I also put the fender washers under the rings so A) I wouldn't have to cut the bolt length from what I already had, and B) they have a rather large hole in them so the rings pretty much seat in them and flex less.

I will try it out later tonight to see if I can put a target on my ST7 Chip both to the East and the West.

It sure LOOKS good! And no longer interferes in anyway with the stock finder.

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This site was last updated 08/10/16

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