Telescope dome slip ring system

Discussion in 'The Projects Forum' started by CyberBill, Aug 13, 2008.

  1. CyberBill

    Thread Starter New Member

    Aug 13, 2008
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    Hi everybody, I am working on a project and wanted to get some ideas and everyone here seems very helpful. :)

    I am in the process of designing an observatory to house a fairly large telescope (20"), and I plan to make it usable remotely over the internet. The telescope itself already has remote control capability, and there will be a small PC inside of the structure itself to control various things. The observatory will be of the dome variety, 12' in diameter and 6' tall, with the dome rotating on 16 pairs of wheels. One (or possibly two) of these will be powered and used to rotate the dome. The upper part of the dome will house some electronics, the biggest power drain will be the motors which control the shutter for the dome, but there will also be some sensors, a wifi router, and a digital camera.

    The issue I have run into is how to power all of these devices. The most popular way to do it I have found is to use a slip ring system. I thought maybe I could run two 1/8" copper pipes (Easily bent!) on the bottom of the dome ring, and then use some motor brushes connected to 110VAC to transfer power to the top, using maybe 10 sets of brushes to minimize skips in the power. I don't know if the voltage is going to make it spark though... I could use a transformer to drop the voltage down to 12VAC and then back up to 110VAC on the top, but I don't know if that would do the trick.

    I am able to put some batteries on the top ring and some capacitors of course to help smooth things out, and using DC instead of AC is possible, as everything should run fine behind an inverter. I just KNOW that there must be a simple, easy to implement, and cheap design, but this just isn't my area of expertise.

    Any help would be very much appreciated! Thanks guys!

    -Bill Carlson
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Why not invert the system and make the motors stationary? Their drive gears, wheels, belts, etc. would turn the dome and or specific sections to create the slot.
    John
     
  3. CyberBill

    Thread Starter New Member

    Aug 13, 2008
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    The motors that turn the dome would be located on the unmoving (bottom) part of the dome, so they don't actually pose a problem. There is no telescope design that I know of that would allow the shutter & motor to remain stationary, the shutter is attached to the dome and rotates when the dome rotates.

    Here is a link to a site that shows construction photos of a dome, so you can see the basic layout: http://www.geocities.com/va3ngc/Astronomy/Projects/ObsDome.html
    This design is much like mine in that the shutter is two pieces, one which rolls over the 'back' of the dome, and the other which flips out in front of the dome, with the top shutter closing on top of the lower shutter to keep it rain proof.

    One reason the design is pretty strict is that great care has to be taken to keep the inside of the dome dry and free of dust, and when the wind is blowing the dome needs to remain fully functional and provide a wind break for the telescope on the inside.
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I misunderstood the design. Thanks for the construction article. I was thinking also that the shutter was formed by rotating the segments of a split dome over each other.

    With one motor on the dome, I suspect you are stuck with a slip ring type of contact. I looked up swivel connectors and there are several at reasonable prices (less than $20) for hair dryers and wall outlets. Here's one example that looked good, but its price was not readily available. John
     
  5. CyberBill

    Thread Starter New Member

    Aug 13, 2008
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    Ohhh!! Thats a good idea! I should definitely pick up a hair dryer and see how they implement their small slip ring. Its gotta work pretty well because hair dryers dont tend to 'skip' when swiveling, and it would obviously be a big hazard if they threw sparks all over the bathroom. ;)

    Thanks for the advice, I'll definitely investigate it!
     
    Last edited: Aug 14, 2008
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