[PIPE2D-381] Leave lamp response in the master flat Created: 06/Mar/19 Updated: 24/Aug/21 Resolved: 24/Aug/21 |
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| Status: | Won't Fix |
| Project: | DRP 2-D Pipeline |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Story | Priority: | Normal |
| Reporter: | price | Assignee: | price |
| Resolution: | Won't Fix | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Story Points: | 2 | ||||||||
| Sprint: | 2DDRP-2019 C, 2DDRP-2019 D, 2DDRP-2019 E, 2DDRP-2021 A 8 | ||||||||
| Description |
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Spectra extracted from the image must have been divided through by the response of the system to the flat-field lamp; that is, we should not make any correction for the effects of the flat-field lamp or the dichroic in the per-arm spectra, and we should not correct the merged spectra for the flat-field lamp spectrum until we look at the spectrophotometric standards (at that point in open-use when no spectrophotometric standards have been observed we may want to do something special/hacky). Currently, this is done by normalising the flat-fields row by row, and putting the lamp response in the fiberTrace. However, we want to reverse this: the flat should not be normalised row by row, and the fiberTrace should be normalised row by row. That flat should be normalised as a whole across the entire instrument, as is done for imaging. |
| Comments |
| Comment by price [ 14/Mar/19 ] |
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I'm not sure it's possible to leave the lamp response in the master flat, because neighbouring fibers may have different response, so it's not clear what the value between them should be. |
| Comment by price [ 01/Apr/19 ] |
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I believe rhl's plan is to construct a separate flat image for each fiber. This will require defining a new flat-field class, which is more work than we were initially considering. hassan, is this something you want to do now? |
| Comment by hassan [ 02/Apr/19 ] |
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This can be re-scheduled for a later sprint as it's not critical on anything, although it's good to clean up earlier. I'll move it to the next sprint. Can you elaborate a little more on what is needed? You need to define a whole new class for flats? |
| Comment by hassan [ 02/Apr/19 ] |
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Actually just talked to @rhl about it, and this particular ticket can be addressed, but without needing - at this stage - to create flat images for each fiber. The work of creating individual fiber images can be done later this year. So this particular ticket will remain in this sprint. |
| Comment by price [ 28/Jul/21 ] |
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rhl is this still something you want to do? Putting the lamp response in the flat would undo the recent work to have pfsArm fluxes in counts. |
| Comment by hassan [ 13/Aug/21 ] |
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rhl will look into this and comment shortly. This could be closed as won't fix and revisit later. |
| Comment by price [ 24/Aug/21 ] |
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In our meeting today, we agreed that the current way we're flat-fielding and normalising is how we want to proceed, at least in the medium-term. |