[PIPE2D-424] Investigate very wide traces Created: 21/May/19  Updated: 21/May/19  Resolved: 21/May/19

Status: Done
Project: DRP 2-D Pipeline
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Task Priority: Normal
Reporter: ncaplar Assignee: ncaplar
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Relates
relates to PIPE2D-415 Sometimes pfsArm has less elements th... Done
Story Points: 2
Reviewers: hassan

 Description   

Paul reports (slack, #drp-2d on Thursday, May 16th, 2019) that when analyzing the exposure with visitid=13183 he finds:

that Here’s the width of each fiber (except the two close to each other):

```0 2.68939032411

1 2.63398771636

2 2.08473567312
3 1.86881057574
4 1.81323757688
5 1.64066318482
6 1.53396636169
7 1.53255265524
8 1.45133603564
9 1.40209867151
10 1.38059525031
11 1.31285056784
12 1.27757783073
13 1.24954811736```
Sure looks like optics to me, what with that tilt.

This would imply huge differences between the PSF on the left and right hand side of the detector. I believe that this data should have been properly aligned, even thought they had the wrong stop (F/3.3)

This ticket is to 1. investigate this claim, 2. see if this is still the case in the data taken with the F/2.8 stop .



 Comments   
Comment by ncaplar [ 21/May/19 ]

1. I have verified that the traced indeed look different and that the analysis done by price is correct.

2. The reason for the error is that the flats have been taken with setting W_ENFCAX= -0.5 / FCA X coordinate, as tracked in the header. This is because the value for W_ENFCAX was not reset, after taking dithered data. I have verified that the data taken beforhand (darks and biases, e.g., 13182) have also W_ENFCAX= -0.5 / FCA X coordinate. As such, this config data is not usable.

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