Axis Calcs

I wanted to locate the vertical axis of the OTA in line with the vertical center of the dome. These calcs are by and large unique for the telescope and wedge used.

(Yes, another Meade 12" LX200KGT setting on a Mitty wedge will be the same.)

So I set up The Beast and thought you may enjoy how I did these things.

These three pix are from the top looking down at the wedge base. I like to align using a cheap 6" level and align paralllel to all three legs. One at a time.

This has become a very easy and quick way of achieving a practical level.

Above is the first leg.

The second.

The third.

Now, we know the wedge base is level and now we need to get an approximate tilt of the wedge based on our latitude.

First, lock the RA down at zero so the tube is kinda vertical.

(The other night, I made certain the angle-o-meter is pretty close to being zero when the scope is horizontal and 90 degrees when it is pointed straight up.)

My location is 45 degrees so I set the angle to that.

Then, using the wedge tilt adjustment, get the OTA so it is straight up.

I carefully put my level on the edge of the scope. And was careful not to knock it down onto the corrector plate.

Keep manually adjusting the wedge until the tube is level.

Will this result in the OTA being absolutely vertical? Probably not.

But it is good enough.

So here is what we have now.

See the little red plug courtesy of Peterson Engineering? That will be the easiect way for us to find a way to hang a string from the center of the OTA. It even has a tiny dimple where the center is.

I removed the diagonal and plopped the plug in.

I poked a hole in the center of the plug and knotted a string and pulled it thru. Put a small socket on the bottom, suspended by a match so the tilt of the socket would nt be too bad for vertical.

A Poor Mans plumb bob.

We want to find the center of the knob, which is the center of the supporting tripod (or pier) and then, measure to our string which is the center of the OTA.

Finding the center of bolts or knobs can be a bit tricky. Here is a shortcut that will work fine.

We will measure from both the front and back of the knob by rotating it just a bit.

Above is one measure, below, another.

From the front.

And the back.

Our front side measurement.

About 5 13/16".

And from the back. About 8 5/16".

Add the two together.

13 18/16th

Which gives us 14 2/16ths

Or 14 1/8"

Divide by 2 and our offset will be

7 1/16"

Or, just plain 7" will be good enough.

We will place the supporting pier/column 7" off center within the dome structure. The hole in the floor also has ot be offset this amount as well.


The inside of the plug.

The socket and matchstick.

The underside.