araichoor
commented
1 month ago I had a look at that.
my understanding is:
- for those early tiles, fiberassign didn t assign any coordinates to the stuck/broken fibers, so the fiberassign
(TARGET_RA, TARGET_DEC)arenan; - in that case, the code falls back to platemaker
(FIBER_RA, FIBER_DEC), which apparently assigns those default values to non-valid coordinates:(200.54410769651886 -50.326107696518925); I guess that the dec=-50 means "this obviously is a non-real value", as desi cannot go that south; - then, the other thing here is that
expid=87354is a split exposure (i.e. same tileid=11 thanexpid=87353); apparently, in that case, platemaker doesn t provide those(FIBER_RA, FIBER_DEC)columns; in that case, I guess that the fibermap code ends up with(TARGET_RA, TARGET_DEC) = (0, 0).
I don t see an obvious way to fix that at the exposure level, as I guess the thing to do would be to use for expid=87354 the coordinates from expid=87353, but as the code is run per-exposure, one cannot play such games.
though, for the cumulative and healpix reductions, one could intercept that with a logic like: if there are split exposures, check the (TARGET_RA, TARGET_DEC) for negative TARGETIDs, and in case of discrepancy use the values of the first exposure.
the relevant part of the fibermap code should be:
https://github.com/desihub/desispec/blob/abfec75c3cd96bd9eca000125fc80aca8afcc4c8/py/desispec/io/fibermap.py#L891-L897
and
https://github.com/desihub/desispec/blob/abfec75c3cd96bd9eca000125fc80aca8afcc4c8/py/desispec/io/fibermap.py#L991-L999
if useful, illustrating what s in the coordinates files:
>>> d = Table(fitsio.read("/global/cfs/cdirs/desi/spectro/data/20210505/00087353/coordinates-00087353.fits","DATA"))
>>> d.colnames
['PETAL_LOC', 'DEVICE_LOC', 'POS_Q', 'POS_S', 'POS_FLAGS', 'POS_X', 'POS_Y', 'TARGET_RA', 'TARGET_DEC', 'FA_X', 'FA_Y', 'FA_FIBER', 'REQ_Q', 'REQ_S', 'REQ_X', 'REQ_Y', 'EXP_Q_0', 'EXP_S_0', 'FLAGS_EXP_0', 'EXP_X_0', 'EXP_Y_0', 'FVC_X_0', 'FVC_Y_0', 'FLAGS_FVC_0', 'CNT_X_0', 'CNT_Y_0', 'FLAGS_CNT_0', 'CNT_MAG_0', 'CNT_ERR_0', 'DX_0', 'DY_0', 'FPA_X_0', 'FPA_Y_0', 'FLAGS_COR_0', 'REQ_X_0', 'REQ_Y_0', 'OFFSET_0', 'EXP_Q_1', 'EXP_S_1', 'FLAGS_EXP_1', 'EXP_X_1', 'EXP_Y_1', 'FVC_X_1', 'FVC_Y_1', 'FLAGS_FVC_1', 'CNT_X_1', 'CNT_Y_1', 'FLAGS_CNT_1', 'CNT_MAG_1', 'CNT_ERR_1', 'DX_1', 'DY_1', 'FPA_X_1', 'FPA_Y_1', 'FLAGS_COR_1', 'REQ_X_1', 'REQ_Y_1', 'OFFSET_1', 'FIBER_RA', 'FIBER_DEC', 'FIBER_X', 'FIBER_Y', 'FIBER_DX', 'FIBER_DY', 'FIBER_OFFSET']
>>> d["FA_X", "FA_Y", "FIBER_RA", "FIBER_DEC"][d["FA_FIBER"] == 1763]
<Table length=1>
FA_X FA_Y FIBER_RA FIBER_DEC
float32 float32 float64 float64
------- ------- ------------------ -------------------
nan nan 200.54410769651886 -50.326107696518925
>>> d = Table(fitsio.read("/global/cfs/cdirs/desi/spectro/data/20210505/00087354/coordinates-00087354.fits","DATA"))
>>> d.colnames
['PETAL_LOC', 'DEVICE_LOC', 'POS_Q', 'POS_S', 'POS_FLAGS', 'POS_X', 'POS_Y', 'TARGET_RA', 'TARGET_DEC', 'FA_X', 'FA_Y', 'FA_FIBER', 'FOR_DX_1', 'FOR_DY_1', 'FOR_X_1', 'FOR_Y_1', 'FLAGS_FOR_1', 'FOR_OFFSET_1', 'EXP_Q_0', 'EXP_S_0', 'FLAGS_EXP_0', 'EXP_X_0', 'EXP_Y_0', 'FVC_X_0', 'FVC_Y_0', 'FLAGS_FVC_0', 'CNT_X_0', 'CNT_Y_0', 'FLAGS_CNT_0', 'CNT_MAG_0', 'CNT_ERR_0', 'DX_0', 'DY_0', 'FPA_X_0', 'FPA_Y_0', 'FLAGS_COR_0', 'REQ_X_0', 'REQ_Y_0', 'OFFSET_0']
>>> d["FA_X", "FA_Y", "FIBER_RA", "FIBER_DEC"][d["FA_FIBER"] == 1763]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/global/common/software/desi/perlmutter/desiconda/20240425-2.2.0/conda/lib/python3.10/site-packages/astropy/table/table.py", line 2071, in __getitem__
[self[x] for x in item], copy_indices=self._copy_indices
File "/global/common/software/desi/perlmutter/desiconda/20240425-2.2.0/conda/lib/python3.10/site-packages/astropy/table/table.py", line 2071, in <listcomp>
[self[x] for x in item], copy_indices=self._copy_indices
File "/global/common/software/desi/perlmutter/desiconda/20240425-2.2.0/conda/lib/python3.10/site-packages/astropy/table/table.py", line 2062, in __getitem__
return self.columns[item]
File "/global/common/software/desi/perlmutter/desiconda/20240425-2.2.0/conda/lib/python3.10/site-packages/astropy/table/table.py", line 265, in __getitem__
return OrderedDict.__getitem__(self, item)
KeyError: 'FIBER_RA'
Tile 11 observed on 20210505 exposures 87353 and 87354 had a set of stuck positioners that got assigned different TARGET_RA, TARGET_DEC for the two exposures.
From kibo/preproc/20210505/00087353/fibermap-00087353.fits
From kibo/preproc/20210505/00087354/fibermap-00087354.fits
It looks like in one case the code is assigning default values to something way off the tile, and in another case assigning them to 0.0 (which I thought we had previously fixed...).
These are all bad targets and thus aren't particularly high priority, but we should understand the bookkeeping of this and get it standardized. It lead to the healpix bookeeping issue in #2354 due to different fibermaps of the same tile covering different healpix.