Some of the details that are not yet shown include the plate for mounting to the tracking mount.
Most of the OTA's that I've seen using Zero expansion carbon fiber tubes, then break the reason for using the carbon tubing by solidly joining the Rear support to the mid ring with a solid aluminum mounting plate...
With any temperature change, that aluminum mounting plate is pushing and pulling constantly as the temperature varies on the 2 plates that it attaches. It also is putting stress on the truss tubes unevenly and changing the spacing between the primary and secondary...
We will use and aluminum mount that mounts solidly to the rear plate and has a precision linear rail and car that attaches to the mid ring. That way any movement due to temperature changes will cause the rail to move smoothly back and forth in the precision car and not cause any change in mirror spacing.
Doc I sure hope that it's up to the task of staying in collmation over long periods of time...
Originally I was going to build the OTA out of steel 2 inch square tubing...but that would have been much TOO heavy and temp changes would still have been an issue, though less than aluminum...I modeled the fisrt one in balsa and was very impressed with just how stiff it really was.
For a 1/4 scale model a load of 5 pounds on one corner caused a deflection of only .005"
I'm looking forward to doing a similar test to the assembled OTA without the mirrors...don't want to chance damaging them.
Regards,
Preston
-------------------- A few I enjoy,
and a few more in the works ;<)
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