The Intelliscope System - Malte's Scope
by Malte Uhl
Edited by Mark De Smet
I had created the
so that others could learn more about the intelliscope system, how to modify
it, and even possibly use the intelliscope system on a non-intelliscope.
In the approximatly 9 months since putting that page up, I recieved
a number of emails from people who were interested in learning more about
the system, and installing it on another scope.   Malte Uhl decided to
give this a try on his Dobsonian and emailed me to let me know the results.
Below is what Malte wrote and pictures he took.   If you would like
to email about the hosting of this page, or the Intelliscope page, you can
Mark De Smet).
If you would like to contact Malte, you can
I first came across the Intelliscope series at last years ITT, which is maybe
Europe's biggest Telescope meeting, held annually in Austria, in the Alps.
While I was not impressed with the optical performance of the 12" on
display, I immediately found the DSC system very helpful and well designed in
terms of ergonomics.   After a bit of a discussion, the dealer promised to
sell to me the Object Locator and two altitude encoders for 250€ (1€ ~ 1.3$).
Of course, he was unable to get hold of another encoder, but finally, I
got what I ordered.   I suspect that he simply took the encoder from
another controller kit.
So finally, I had the computer, two encoders and the wires, but not the
connector board.   I didn't want it anyway, because it requires a hole in
the rocker box for the socket for the computer.   I fixed a small circuit
board for that.
Thre problems had to be overcome to make the Object locator usable with my
Problem 1 was solved by getting a specially made bearing, that consists of a
mounting plate and a coaxial cylinder, essentially the same thing as the
bushing depicted on your web page, but screwed to the lower half of my rocker
- 1) The upper and lower part of my rocker box were connected only with a bolt
and washer, so that there was lots of play in horizontal direction.
- 2) Mount the altitude controller in such a way that the one practicality
feature of Dobsons, simply lifting the telescope off of the rocker box can be
- 3) Wiring
Problem 2 remains to be solved.   Currently, the altitude encoder is simply
screwed to bearing.   Their diameter is smaller than the circuit board of
the encoder, so I simply use a long screw through in the rocker box to keep the
board from moving in altitude with the encoder disc.   I'm thinking about
clamping the circuit board to the rocker box so that it can be attached and
detached without tools.
Problem 3) Wiring turned out to be unexpectedly tricky.   The spiral cord
connecting the object locator is made from wires that simply cannot be
soldered reliably to anything.   The conductors are very thin and break
easily.   So I got another RJ-11 connector with non-spiral wires.
Anyway, the wiring diagram you've given is correct.   I used an
experimental circuit board instead of the connector board since I had not
decided on which way to mount the encoders.   I believe that it is
possible to reverse the encoders directions by simply "swapping" the hall
encoders by crossing their connections.
After everything was mounted and connected, the system worked perfectly at
first try.   I was particularly impressed by the pointing accuracy.
Using Vega and Capella as alignment stars, precision was good enough to have
all targets visible in my lowest power eyepiece, which gives about 1.5° field
of view.   The warp factor is always in the range of 0.3-0.8.
The above picture shows the rockerbox from below with the upper and lower
This picture shows the bolt and bushing that originally connected the
two peaces.   Essentially, it's only keeping them from falling apart, allowing
lots of lateral play, which makes it unusable for precise angular measurements.
It had to be replaced with the purpose built part depicted in
above.   The base plate gets firmly attached to the bottom part,
leaving only minimal play to still allow the upper part to rotate easily.
This is shown in the next 5 photos.
This shows the two altitude encoders.   The second one was cut to
15mm length, to avoid interference with the moving telescope.   I really didn't
want to change the altitude bearings of my rocker box.   The next two pictures show
how I attached the encoder to the bolt in the center bearing.   No, the circuit
board is not bent.
This shows what the altitude bearing looked like originally.   The
telescope once was a GSO880.   It has the typical spring load mechanism used by
These three show that I simply removed the black plastic bushing from
the altitude bearing instead putting the altitude encoder in place.   By lucky
coincidence, it fits perfectly!
In the above picture you can see all the bits and pieces connected
experimentally.   And the last picture shows the posessions of one happy Orion
customer in action.
So, I hope you like it and that my pictures may be helpful to others.   Things
remaining to be done obviously are
- - attach cabling properly
- - provide better support for the encoder circuit boards
- - make the altitude encoder attachable/detachable without tools
here to return to Mark's projects page.