As a check on the optical properties of the telescope, I went back to look at some focus test images taken on nights between Jan 16 and Jan 28, 2016. Unfortunately, since we were not planning to check the optical properties of the telescope when we took the focus images, these tests do not cover a wide range of focus positions in a systematic manner; they simply allowed us to find an approximate position for best focus on any particular night.
The collection of images here come from 3 different nights, and so are rather inhomogenous. I chose individual stars in each of the four corners of the chip, with the orientation in the images like so:
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| South |
| 1 2 |
| |
| |
|West East|
| |
| 4 3 |
| North |
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Each set of 4 closeups below shows the stars 1, 2, 3, 4, in that order, clockwise from upper left. In other words, the closeups below show stars in the corners matching the diagram above. Positions relative to the best focus are only estimates.
c7408t0040: pos = -350.
c7415t0058: pos = -160.
c7406t0078: pos = -150.
c7408t0043: pos = +150.
c7406t0080: pos = +250.
Click on the link below to run an animation showing all five above frames in row.
