Last updated: 26 January 2007
Subject:	ETX-ZOOM
Sent:	Wednesday, January 24, 2007 12:22:42
found your ETX-side a few hours ago and maybe this is of interest for
anybody.  Since a few days i own a ETX 90-PE mount(not the optic) and
fixed -due to lack of ETX OTAs- a Soligor Zoom lens 500-800mm in the
tang-arms of the mount. Easy. A piece of wood 2 screws each side, a hole
for the foto-screw, thats it.
Nice but useless ;))


Mike here: Now all you need is an AutoStar #497 and you could control the "telescope".


i thought i am too stupid when trying to use the Autostar as the scope
pointed always anywhere but not to the selected object. It took a few
hours (right now) to find out that this kind of mounting a scope to the
ETX is basically wrong.

Why ? well, it now has a wrong angle of 90 degrees. The scope must point
in the direction of the two tangential-arms and not misplaced by 90,
right ?

Poooh ! now i need another solution how to fasten a scope (which has not
the ETX tubering) on my ETX. But tell me: would you refuse a
ETX+Autostar for 50 bucks ?   ;))
Just kidding....

I searched your site but did not find a hint that somebody uses another
scope on the ETX. Well, its a ETX side ;)

But maybe you have an idea ?

would be pleased to hear from you again..

greetings from Luebeck NorthGermany
Mike here: Hum, that's true about the fork arm adapters. Maybe our resident AutoStar expert Dick Seymour has an idea about changing the AutoStar to handle that.


i guess it is a question of the stoppers inside the RA drive fork. The
Autostar and the encoders dont care how a scope is mounted.

How about modyfing them:

--disassemble (and replace somewhere else)for non-ETX use
--assemble again for ETX use
dont know how to fix that yet.

replace the finger at RA-drive fork-side. The finger
rotates against the stoppers, blocking the RA within 90 area.

If i would try to rotate the finger by 90 ....
...yeahh, i think that is the solution.
Unfortunately you can not turn the finger....

understand what i mean or shall i make a foto ?

best regards
Mike here: True there are hard stops that will be a problem. Your solutions might work.
From:	richard seymour (
You have three ways to "fix" your problem:

(1) In the Autostar, simply change the -sign- of the Alt/Dec Ratio.
  (setup>telescope>Alt/Dec Ratio).  That will reverse the fork motors,
  and the Soligor will be able to explore the heavens.
  It will still not be able to drop -below- horizontal, but it will
   be able to go "up".
 (you change the sign by moving the cursor left with the slew arrow,
 then tap the scroll arrow to change it from + to - )

(2) rework your "cradle" so that the original ETX support is
  "behind" the lens, instead of under it.

(3) open the motor-side fork and remove the "hard stop".
 I don't know which model (new/old) ETX90 you have.  The only
 DEC hard stop i have seen "removed" was an ETX105 which broke
 the metal casting (see:
and scroll far down to the photo, or search for the name "Hawkins")
There is probably a corresponding plastic bit on the rotating
 component that might be easier to remove.

have fun


One more thing... turn the Soligor around so it is facing
-away- from the RA/Az Clamp handle.

As shown in the photo there is a second hard stop which
will prevent further "up" motion, but if you arrange it
so that the motor fork is on the -right- when you are
behind the camera, then the cradle will be able to point the
lens straight up (and over)

have fun

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