Automate Astronomy Dome - Help

I am interested in building an electronic system to control the orientation of an astronomy dome based on the orientation of the telescope. I need suggestions on the various components I might use. Motivation: This is a Meade 16" LX200 telescope in an Ash Dome. Owned by a friend who doesn't use it much. I get to use it, maintain it, enhance it for about 1 week a year. I can control the scope with my laptop using a program like "The Sky". However, after the telescope is pointed, I have to manually manage the dome and rotate it with a bi-directional switch. Very tedious. The motor is 1/4 HP, 1725RPM, drawing 5.6 Amps at 120VAC. There are programs that can be used with the telescope control to manage the rotation of the dome, but I am thinking of a lower-tech solution. I would like to put some reflecting tape (perhaps mirrors) on the sides of the dome slot and point some lights (perhaps LED lasers) with a pickup device (hence the idea of the garage door styled "electronic eye"). The general idea would be to set up some simple device that would detect the change in location of the direction that the telescope is pointing, and activate the dome to track with the telescope. If the telescope turns, the light would no longer be reflected and the dome would try to "find" itself or re-orient to a point where the light is once again detected by the reflection from the mirrors on the dome. I was thinking about: Garage door electronic eye activators 120V 6A relay switches 2 enhancements: detect direction of the telescope; bar codes in the reflective tape wireless signals to send activation to relay switches (telescopes go in circles and eliminating wires is always good.) Anyone have any ideas about pre-built components, sources of good relays, electronic eyes, etc? TIA, Chris.

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NachoMahma9 years ago
. Moved from Help:feedback to Forums:Science.
chrisjx (author)  NachoMahma9 years ago
Thanks. I guess I intended it to be under the Burning Questions section. But this is fine. As long as some folks see it. The way I posted was awkward. I registered and I guess the feedback section was the default. Anyway, thanks.
. No problem. Topics in the Help forums don't show up in the All list. Maybe it will get a few eyeballs here.
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. I've been pondering your question and I'm thinking some type of rotary encoder that is driven by the dome (mount near positioning drive?) would tell you the position of the dome. Compare that to the position of the 'scope (from computer?). Just don't ask me how to actually do it.
. The bi-directional switch can be replaced/paralleled by relays.
chrisjx (author)  NachoMahma9 years ago
NachoMahma, I'm trying to keep the computer out of the equation, so to speak. There are already computer programs to track with the telescope (because the position is known based on programs like "The Sky" that allow me to control position of the scope). I am looking for a lower-tech solution because the computer approach needs a lot of custom math; custom dome size (diameter and opening size), the scope is not centered within the circumference of the dome, etc. My solution is to put some light detectors on the telescope. As the telescope rotates, the dome system would simply try to keep the dome opening located/syncronized with the telescope's position. Ideally, this would also be a wireless solution, because wires always get twisted up as the telescope rotates. I uploaded a visio diagram to show the layout of the components. Thanks, Chrisjx
. Or maybe you could adapt the control circuitry of an antenna rotor (not a recommendation, just the first hit that had decent pics).
. Until someone comes along that knows what they are talking about, maybe we can do a little brainstorming.
. How about using a microcontroller? Something like the Arduino or PIC? I'm not familiar with these, but there are some related groups on Ibles. If that sounds like a viable option, ask in the Arduino or The 'uC group(s). May be possible to get 'scope orientation directly from the 'scope using a uC, then all you have to figure out is how to tell where the dome is. The encoder I mentioned should work great with a uC. Using a uC should make compensating for the axis offset pretty easy - eiher compute it on the fly or use a lookup table/interpolation.