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Secondary Holder

Started by hakescl, 04/16/2002 02:05PM
Posted 04/16/2002 02:05PM Opening Post
I am guessing that someone has tried using wire or fishing line to hold a secondary mirror. What is the downside? There must be one, or else it would be done more often. I am sure you would need a relatively long holder so the wires attach away from each other.

Charlie

Fort Lewis Observatory: (37.238, -108.052) ~2360m (7744 ft.) elevation.
Darkness - typically 6.5+
Scope - Meade 16" LX200; f6.3 focal reducer
Focus - JMI Smart focus
Camera - SBIG ST-10XE; (~.5"/pixel)
Guiding - AO-8 and/or Meade 5"/DSI/PHD
http://www.fortlewis.edu/observatory
Posted 04/16/2002 02:38PM #1
I've heard it works. I think the main main difficulty to overcome is vibration--taught strings and wires vibrate rather well, as evidenced by their use on musical instruments. Note that good spiders are pretty thin to begin with and aren't nearly as good for playing music. :-)
--
Mike
Posted 04/16/2002 07:11PM #2
I am no expert as you can tell by my own post. But Mark's comment about string musical instruments got me to think that if you wanted to try this out, You could use a guitar string attached to a peg end and a guitar tuner on the other end, to tension the string. A locking tuner would be a nice choice. This would allow you to tension the strings pretty tightly as well as experiment with different gauges and tensions. Use two pegs and two tuners, to make a cross hair pattern and then tap for holes into the back of a secondary holder, position the holder and use a round backing plate and four screws to hold it in place. Perhaps a groove in the backing plate would be necessary since the strings would overlap.
Anyway it is just a thought. Plus if it gets cloudy you could always play a little foggy mountain breakdown.