Re: ATM Flat mounting plate for solid tube?

[Juan Herrero <jherrero@videotron.ca>]

> Does anyone have experience installing a flat mounting plate on a solid
tube.  I figured if I could do that it would be easier to square the focaser
if there was a mounting plate that was square to attach it to.  Seems it
would be alot sturdier as well.

Yes
Mounting plates can provide many other advantages besides rock solid
focusers.
In my case. While running my commercially made telescope specs through the
telescope design program NEWT25. I discovered that the light cone from the
4" diagonal was seriously vignated by the bottom of the focuser tube.Worse!
the focuser hole on the telescope tube was not big enough to pass the light
cone ! BAD COMMERCIAL DESIGN !!!

One solution was to move the secondary away from the primary and to make a
new focuser hole in the tube. I did not want to do that.
 Instead. I mounted a wood focuser plate with a 3.5" hole . And enlarged the
tube hole to match. Then I  mounted the focuser on a 1/8" aluminum plate
with 8 screws in push/pull formation (4 pull, 4 push) that way you can
adjust the squareness of the focuser during collimation.
Then I mounted the aluminum plate on the wood plate with four screws with
large heads. The four screw  holes on the aluminum plate are large so  you
can  slide it around over the wood plate before tightening it. That way. You
can center adjust the focuser over the secondary mirror.

The ability to fully and easily adjust  a solid focuser,  is very
advantageous when critically collimating an scope for atrophotagraphy.

In any case I strongly advise you to run your design through NEWT25. It will
greatly help you to figure the focuser position and most other parameter of
your design.
You can download NEWT25 at.
 http://www.users.uswest.net/~dalekeller/newtsoft.htm

I also have a large sonotube telescope. If you want I can send you a pic.
If you zoom over the focuser you'll get an idea of how the focuser plate is
built.

Thanks
Juan