Details
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Type:
Improvement
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Status: Done
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Resolution: Done
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Fix Version/s: None
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Component/s: ts_aos
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Labels:
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Story Points:3
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Epic Link:
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Team:Telescope and Site
Description
- Turn off all perturbations again, but this time use the cmd file to add back 1 Zernike perturbation at a time to M1 only. I’d suggest an amplitude of maybe 250 nm.
- Single star on the boresight.
- For each Zernike index 4-22 (or some subset if this is too much), make a plot of the estimated Zernike coefficient vs input rotation angle. You should get sine waves for these, with periods as follows:
- Z4, Z11, Z22 estimated Zernikes are independent of input rotation angle.
- Z7, Z8, Z16, Z17 period is 360 degrees
- Z5, Z6, Z12, Z13 period is 180 degrees
- Z9, Z10, Z18, Z19 period is 120 degrees
- Z14, Z15, period is 90 degrees
- Z20, Z21, period is 72 degrees
- I predict that the above are periodic with rotTelPos, but not rotSkyPos.
- Note that phosim injects circular Zernikes, but ts_wep is estimating annular Zernikes, so we don’t expect to recover 2*250 nm (reflection so path length changes by 500nm!) if we inject a 250 nm perturbation.
Attachments
Issue Links
- is child task of
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DM-33116 Validate AOS for a rotated camera
- Done
Activity
Comparison of donut postage stamps given a single input zk (18) for a variety of `rotTelPos`, allowing PhoSim to calculate `rotSkyPos`. As above, the number in each stamp is the value of angle input in the simulation, in that case `rotTelPos`:
In summary, as mentioned here https://lsstc.slack.com/archives/C9BEJU1T3/p1649452191399489?thread_ts=1649278238.043959&cid=C9BEJU1T3 , these tests prove that "rotTelPos in phosim_syseng4 is really just rotSpiderPos", i.e. the camera is kept at a fixed angle wrt M1M2, and the only thing that rotates due to changing "rotTelPos" is the spider.
In summary, I think we can say convincingly that this proves that there is no camera rotation imparted by 'rotTelPos', only the spider rotation. The camera is at a fixed angle wrt M1M3 assembly. This is similar to the findings of https://jira.lsstcorp.org/browse/DM-31532.
This one looks done.
Comparison of donuts given a single zk for a variety of `rotSkyPos`, keeping rotTelPos=0. The number in each postage stamp is the value of 'rotSkyPos' in that simulation.