| Summary: | These files contain the per-exposure QA measurements. Those are propagated when making coadd reductions, and helps to decide during operations if the observation is valid or not. |
|---|---|
| Naming Convention: | exposure-qa-{expid}, where {expid}
is the 8-digit exposure ID. |
| Regex: | exposure-qa-[0-9]{8}\.fits |
| File Type: | FITS, 441 KB |
| Number | EXTNAME | Type | Contents |
|---|---|---|---|
| HDU0 | IMAGE | Keywords only | |
| HDU1 | FIBERQA | BINTABLE | Per-fiber information table |
| HDU2 | PETALQA | BINTABLE | Per-petal information table |
No data, checksum/datasum header keywords only.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
======== ================ ==== ==============================================
KEY Example Value Type Comment
======== ================ ==== ==============================================
CHECKSUM C4gFE4Z9C4fCC4Z9 str HDU checksum updated 2021-07-16T14:31:54
DATASUM 0 str data unit checksum updated 2021-07-16T14:31:54
======== ================ ==== ==============================================
Empty HDU.
EXTNAME = FIBERQA
This table contains the per-fiber information which helps to decide if the observation is valid or not. That information is also used to define some column content of the PETALQA extension.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
============= =================== ===== ==============================================
KEY Example Value Type Comment
============= =================== ===== ==============================================
NAXIS1 86 int length of dimension 1
NAXIS2 5000 int length of dimension 2
NIGHT 20210514 int Exposure night
EXPID 88364 int Exposure ID
NGOODFIB 4611 int Number of fibers with EFFTIME_SPEC above the threshold
NGOODPET 10 int Number of petals with good fibers
WORSTRDN 5.072375888924774 float Worst read noise for all amplifiers of all cameras
FPRMS2D 0.01157238915902728 float [mm] RMS of the positioners accuracy (measured-requested) in the CS5 location of the focal plane
PMINEXPF [1]_ 0.8370916420971888 float Deprecated
PMAXEXPF [1]_ 1.27911264193688 float Deprecated
EFFTIME 217.9705047607422 float [s] Spectroscopic effective time
TILEID 21181 int Tile ID
EXPTIME 589.277 float [s] Tile exposure time
MJD-OBS 59349.20075297 float [d] Modified Julian Date of observation
TARGTRA 199.993521 float [deg] Target right ascension (to TCS)
TARGTDEC 32.447031 float [deg] Target declination (to TCS)
MOUNTEL 84.320435 float [deg] Mount elevation angle
MOUNTHA -6.689017 float [deg] Mount hour angle
AIRMASS 1.004188 float Airmass
ETCTEFF [1]_ 1015.311096 float [s] Effective time computed (on-the-fly) by the ETC
TILERA 199.992 float [deg] Tile center Right Ascension
TILEDEC 32.447 float [deg] Tile center Declination
GOALTIME [1]_ 180.0 float [s] Aimed EFFTIME_SPEC
GOALTYPE [1]_ BRIGHT str Sky conditions used for some noise estimation
FAPRGRM [1]_ bright str Program to which this tile belongs
SURVEY [1]_ main str Survey of origin of the targets
EBVFAC [1]_ 1.02512649227135 float 10.0 ** (2.165 * median(EBV) / 2.5))
MINTFRAC [1]_ 0.85 float Fraction of GOALTIME to be reached by EFFTIME_SPEC to consider the tile has completed
CHECKSUM YP2AYM16YM1AYM13 str HDU checksum updated 2021-07-16T14:31:54
DATASUM 2084006317 str data unit checksum updated 2021-07-16T14:31:54
============= =================== ===== ==============================================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | Unique target ID | |
| PETAL_LOC | int16 | Petal location [0-9] | |
| DEVICE_LOC | int32 | Device location on focal plane [0-523] | |
| LOCATION | int64 | Location on the focal plane PETAL_LOC*1000 + DEVICE_LOC | |
| FIBER | int32 | Fiber ID on the CCDs [0-4999] | |
| TARGET_RA | float64 | deg | Target Right Ascension |
| TARGET_DEC | float64 | deg | Target Declination |
| FIBER_X | float64 | mm | Fiber CS5 X location on focal plane |
| FIBER_Y | float64 | mm | Fiber CS5 Y location on focal plane |
| DELTA_X | float64 | mm | Fiber difference between measured and requested CS5 X location on focal plane |
| DELTA_Y | float64 | mm | Fiber difference between measured and requested CS5 Y location on focal plane |
| EBV | float32 | mag | Galactic extinction E(B-V) reddening |
| QAFIBERSTATUS | int32 | Fiber status bitmask, inflated with further QA diagnoses | |
| EFFTIME_SPEC | float32 | s | Spectroscopic effective time, based on template-based squared signal-to-noise ratio |
EXTNAME = PETALQA
This table contains some per-petal QA information which helps to decide if the observation is valid or not, and if a petal should be considered as "bad" (i.e. as if it would not have been observed), because of a too-low quality.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
======== ================ ==== ==============================================
KEY Example Value Type Comment
======== ================ ==== ==============================================
NAXIS1 62 int length of dimension 1
NAXIS2 10 int length of dimension 2
CHECKSUM 8aaf9WRc8aXc8WXc str HDU checksum updated 2021-07-16T14:31:54
DATASUM 666368269 str data unit checksum updated 2021-07-16T14:31:54
======== ================ ==== ==============================================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| PETAL_LOC | int16 | Petal location [0-9] | |
| WORSTREADNOISE | float32 | Worst read noise (each individual value being the worst across amplifiers) | |
| NGOODPOS | int16 | Number of valid positioners | |
| NGOODFIB | int16 | Number of good fibers | |
| NSTDSTAR | int16 | Number of standard stars used by the spectroscopic pipeline for calibration | |
| STARRMS | float32 | RMS of the r-band flux ratio of standard stars | |
| TSNR2FRA [1] | float32 | Deprecated | |
| EFFTIME_SPEC | float32 | s | Median of the EFFTIME_SPEC values for all good fibers from that petal |
| NCFRAME | int16 | Number of cframe files for that petal | |
| BSKYTHRURMS | float32 | Sky throuput RMS for the b-camera | |
| BSKYCHI2PDF | float32 | Reduced chi2 for the sky fibers for the b-camera | |
| RSKYTHRURMS | float32 | Sky throuput RMS for the r-camera | |
| RSKYCHI2PDF | float32 | Reduced chi2 for the sky fibers for the r-camera | |
| ZSKYTHRURMS | float32 | Sky throuput RMS for the z-camera | |
| ZSKYCHI2PDF | float32 | Reduced chi2 for the sky fibers for the z-camera | |
| BTHRUFRAC | float32 | Relative (single petal vs. all petals) throughput for the b-camera | |
| RTHRUFRAC | float32 | Relative (single petal vs. all petals) throughput for the r-camera | |
| ZTHRUFRAC | float32 | Relative (single petal vs. all petals) throughput for the z-camera |
| [1] | Optional |
- These
exposure-qa-{expid}files are used to compute several of the :doc:`tile-qa-TILEID-GROUPID <../../../tiles/GROUPTYPE/TILEID/GROUPID/tile-qa-TILEID-GROUPID>` entries. - The QAFIBERSTATUS bitmasks are defined here :doc:`bitmasks <../../../../../../bitmasks>`.
- Some FIBERQA extension header keywords are originally coming from the :doc:`fiberassign-TILEID <../../../../../DESI_TARGET/fiberassign/tiles/TILES_VERSION/TILEXX/fiberassign-TILEID>` file (TILEID, TILERA, TILEDEC, GOALTIME, GOALTYPE, FAPRGRM, SURVEY, EBVFAC, MINTFRAC).
- The FIBERQA EFFTIME_SPEC is proportional to the TSNR2 values in the TSNR2 extension of the :doc:`redrock-SPECTROGRAPH-TILEID-GROUPID <../../../tiles/GROUPTYPE/TILEID/GROUPID/redrock-SPECTROGRAPH-TILEID-GROUPID>` file; for the BACKUP and BRIGHT programs, the TSNR2_BGS is used; for the DARK program, the TSNR2_ELG or TSNR2_LRG is used.
- For the SURVEY=cmx m33 tile (TILEID=80615) tile and all the SURVEY=sv1 tiles (except TILEID=80971-80976, the dc3r2 ones), proper-motion correction was applied at the :doc:`fiberassign </DESI_TARGET/fiberassign/tiles/TILES_VERSION/TILEXX/fiberassign-TILEID>` design step; thus the following columns can have different values than in the :doc:`desitarget products </DESI_TARGET/TARG_DIR/DR/VERSION/targets/PHASE/RESOLVE/OBSCON/PHASEtargets-OBSCON-RESOLVE-hp-HP>`:
TARGET_RA,TARGET_DEC,REF_EPOCH,PLATE_RA,PLATE_DEC, andPLATE_REF_EPOCH.