[INSTRM-1675] Investigate why fiber was off the target in the 2022 June run Created: 27/Jul/22  Updated: 02/Oct/22  Resolved: 02/Oct/22

Status: Done
Project: Instrument control development
Component/s: pfs_utils
Affects Version/s: None
Fix Version/s: None

Type: Task Priority: Normal
Reporter: yuki.moritani Assignee: yuki.moritani
Resolution: Done Votes: 0
Labels: EngRun
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Blocks
is blocked by INSTRM-1676 Modify sky-pfi transformation to fina... Done
is blocked by INSTRM-1692 Make sky-pfi coordinate transformatio... Done
is blocked by INSTRM-1706 renew FF positions based on measureme... Done
Story Points: 3
Sprint: preEngRun07Sep

 Description   

In the 2022 June run, the raster scan tests revealed there is a large offset and rotation between the targets position and cobras position. We found that one possible root cause is discrepancy in FF definition between mcs-pfi and sky-pfy transform. In the former, pfiTransform takes account into the FF position measured by XY scanner, while the latter uses designed positions. There should be other reasons, but we will start with correct discrepancy in FF position definition.

Note that Richard and Kawanomoto-san checked XY scanner data (again) and confirmed FF, Cobra and AG position are in the same plane in general.

 Comments   
Comment by yuki.moritani [ 15/Sep/22 ]

Jim, Robert, Craig, Hassan, Kawanomoto-san, Yoshida-san, Tamura-san , Shiang-Yu and I had a meeting to discuss the report by Kawanomoto-san sent to PFI mailing list (PFI: 2761). The agreement is

  • Update FF position on pfs_insdata using AG CCD observation
  • Modify pfs_utils routines which assume the FF position in XY scanner plane is correct

For reference, the latest version of the report by Kawanomoto-san is here: https://sumire.pbworks.com/w/file/150405840/PFS-PFI-NAJ802206-02_Coordinates.pdf

Comment by yuki.moritani [ 02/Oct/22 ]

Following the change of FF positions, the dot and cobra centers were also changed before the September 2022 run, although these positions were re-measured during the run.

By updating FF position, we succeeded in putting the targets on (or nearby) the fibers. So this ticket can be closed.

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