Better Measurements of the Pier Locations
We’ve measured the pier locations before but the fabrication of the bogey rocker box azimuth supports – what the entire telescope will sit on top of, prompted us to re-measure, just to make sure. The design up until now had the piers each at the corner of an equilateral triangle, all sides measuring 45 inches. Larry’s more careful measurement last weekend put the three sides at 45.5, 48.0 and 45.75 inches – not even close to equilateral.
The effect on the design turned out to be minor. Any triangle has a circle that contains its three points and it was a fun geometry challenge to figure out how that circle changed with the new triangle side measurements. Since the design of the rest of the telescope has a natural symmetry axis through the optical axis, I left that where it was and just moved the piers so that they reflected the new data. This PDF takes you through the math, including some illustrations of how the pier positions changed.
The impact on the base of the rocker bogeys is that we moved the piers out from under them by about 0.75-inch. There is still probably enough material over the pier cap to attach them solidly, but since the rocker bogey base width is about 3.75-in, we can increase that to 4.00-in just to give us a little more purchase on the pier cap
Larry also ended up confirming the position of the floor with respect to the pier caps and that means that we still have a little over half an inch of clearance between the bottom of the azimuth drive assembly and the floor – more than enough!
The Drawings tab has a set of images with the design changes under New Pier Placement.