fibermap-EXPID

Summary:

The fibermap contains the fiber positioner configuration information for each exposure: what fiber is placed where, what target that is, etc. This file type only appears in raw data from 2018 and should be considered obsolete.

Naming Convention:

fibermap-{EXPID}.fits, where {EXPID} is the 8-digit exposure ID.

Regex:

fibermap-[0-9]{8}\.fits

File Type:

FITS, 2 MB

This table is also propagated forward to the frame, cframe, and spectra files.

Contents

Number	EXTNAME	Type	Contents
HDU0	PRIMARY	IMAGE	Blank
HDU1	FIBERMAP	BINTABLE	Fiber map table of what targets are on what fibers
HDU2	TARGETS	BINTABLE	Row matched target catalog for those assignments

FITS Header Units

HDU0

EXTNAME = PRIMARY

Empty HDU.

This HDU has no non-standard required keywords.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	0	int
TILEID	1165	int
REQRA	150.69	float
REQDEC	33.86	float
TILERA	150.69	float
TILEDEC	33.86	float
REFEPOCH	2015.5	str
NIGHT	20201010	int
EXPID	123456	int
FLAVOR	science	str
FIELDNUM	0	int	Field configuration number for this tile
TELRA	150.6899871709776	float
TELDEC	150.6899913445232	float

Data: FITS image [float64, 0]

HDU1

EXTNAME = FIBERMAP

The fiber map table of which targets where placed on which fibers at which locations. This is a superset of the requested fiberassignments, augmented with columns describing where the fibers actually ended up.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	378	int	length of dimension 1
NAXIS2	5000	int	length of dimension 2
NIGHT	20170327	str	YEARMMDD of sunset for this night
EXPID	2	int	unique DESI exposure ID
TILEID	4	int	DESI tile ID
PROGRAM	DARK	str	program [dark, bright, gray, calib, …]
FLAVOR	science	str	Flavor [arc, flat, science, zero, …]
REQRA	335.03	float	Requested telescope RA [degrees]
REQDEC	19.88	float	Requested telescope dec [degrees]
REQRA	335.03	float	Requested telescope RA [degrees]
REQDEC	19.88	float	Requested telescope dec [degrees]
TELRA	335.03	float	Actual telescope pointing RA [degrees]
TELDEC	19.88	float	Actual telescope pointing dec [degrees]
AIRMASS	1.17754	float	Airmass at middle of exposure
EXPTIME	629.827	float	Exposure time [sec]
SEEING	0.7769	float	Seeing FWHM [arcsec]
MOONFRAC	0.4083	float	Moon illumination fraction 0-1; 1=full
MOONALT	-72.8225	float	Moon altitude [degrees]
MOONSEP	131.1832	float	Moon:tile separation angle [degrees]
DATE-OBS	2020-03-17T03:35:05.835	str	Start of exposure

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique target ID
FIBER	int32		Fiber ID on the CCDs [0-4999]
PETAL_LOC	int16		Petal location [0-9]
DEVICE_LOC	int32		Device location on focal plane [0-523]
LOCATION	int32		Location on the focal plane PETAL_LOC*1000 + DEVICE_LOC
FIBERSTATUS	int32		Fiber status mask; 0=good
OBJTYPE	char[3]		SKY, OBJ, NON
DESI_TARGET	int64		Dark survey + calibration targeting bits
BGS_TARGET	int64		Bright Galaxy Survey targeting bits
MWS_TARGET	int64		Milky Way Survey targeting bits
SECONDARY_TARGET	int64		Secondary targets targeting bits
COMM_TARGET	int64		Commissioning targeting bits
SV1_DESI_TARGET	int64		Survey Validation targeting bits
SV1_BGS_TARGET	int64		Survey Validation targeting bits
SV1_MWS_TARGET	int64		Survey Validation targeting bits
TARGET_RA	float64	deg	Target Right Ascension [degrees]
TARGET_DEC	float64	deg	Target declination [degrees]
TARGET_RA_IVAR	float32	deg^-2	Inverse variance of TARGET_RA
TARGET_DEC_IVAR	float32	deg^-2	Inverse variance of TARGET_DEC
LAMBDA_REF	float32	Angstrom	Wavelength at which targets should be centered on fibers
DESIGN_X	float32	mm	Expected CS5 X location on focal plane
DESIGN_Y	float32	mm	Expected CS5 Y location on focal plane
DESIGN_Q	float32	deg	CS5 Q azimuthal coordinate
DESIGN_S	float32	mm	CS5 S radial distance along curved focal surface
BRICKID	int64		Imaging Surveys brick ID
BRICK_OBJID	int64		Imaging surveys OBJID on that brick
TYPE	char[4]		Imaging surveys morphological type
PRIORITY	int32		Assignment priority; larger = higher priority
SUBPRIORITY	float64		Assignment subpriority [0-1]
NUMTARGET	int16		Total number of targets that this positioner covered
REF_ID	int64		Astrometric catalog reference ID (SOURCE_ID from GAIA)
PMRA	float32	mas/yr	Proper motion in the RA direction (already including cosDec term)
PMDEC	float32	mas/yr	Proper motion in the dec direction
PMRA_IVAR	float32		Inverse variance of PMRA
PMDEC_IVAR	float32		Inverse variance of PMDEC
FLUX_G	float32	nanomaggies	Flux in g-band
FLUX_R	float32	nanomaggies	Flux in r-band
FLUX_Z	float32	nanomaggies	Flux in z-band
FLUX_W1	float32	nanomaggies	Flux in WISE W1-band
FLUX_W2	float32	nanomaggies	Flux in WISE W2-band
FLUX_IVAR_G	float32		Inverse variance of FLUX_G
FLUX_IVAR_R	float32		Inverse variance of FLUX_R
FLUX_IVAR_Z	float32		Inverse variance of FLUX_Z
FLUX_IVAR_W1	float32		Inverse variance of FLUX_W1
FLUX_IVAR_W2	float32		Inverse variance of FLUX_W2
FIBERFLUX_G	float32	nanomaggies	g-band object model flux for 1 arcsec seeing and 1.5 arcsec diameter fiber
FIBERFLUX_R	float32	nanomaggies	r-band object model flux for 1 arcsec seeing and 1.5 arcsec diameter fiber
FIBERFLUX_Z	float32	nanomaggies	z-band object model flux for 1 arcsec seeing and 1.5 arcsec diameter fiber
FIBERTOTFLUX_G	float32	nanomaggies	like FIBERFLUX_G but including all objects overlapping this location
FIBERTOTFLUX_R	float32	nanomaggies	like FIBERFLUX_R but including all objects overlapping this location
FIBERTOTFLUX_Z	float32	nanomaggies	like FIBERFLUX_Z but including all objects overlapping this location
FIBER_RA	float64	deg	RA of actual fiber position
FIBER_DEC	float64	deg	DEC of actual fiber position
FIBER_RA_IVAR	float32	deg^-2	Inverse variance of FIBER_RA [not meaningful yet]
FIBER_DEC_IVAR	float32	deg^-2	Inverse variance of FIBER_DEC [not meaningful yet]
DELTA_X	float32	mm	CS5 x difference between requested and actual position
DELTA_Y	float32	mm	CS5 y difference between requested and actual position
DELTA_X_IVAR	float32	mm^-2	Inverse variance of DELTA_X [not meaningful yet]
DELTA_Y_IVAR	float32	mm^-2	Inverse variance of DELTA_Y [not meaningful yet]
NUM_ITER	int16		Number of positioner iterations
SPECTROID	int16		Hardware ID of spectrograph (not used)

HDU2

EXTNAME = TARGETS

Target catalog row-matched to the FIBERASSIGN table entries. Unassigned fibers will have TARGETID=-1 here.

Note: Software release 18.11 (desispec/0.26.0 desisim/0.31.0) does not include this HDU. In the future it will either be included or deprecated and removed.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	184	int	length of dimension 1
NAXIS2	5000	int	length of dimension 2
TNULL1	999999	int
TNULL3	999999	int
TNULL31	999999	int
TNULL32	999999	int
TNULL33	999999	int
TNULL34	999999	int
TNULL35	999999	int
TNULL36	999999	int
ENCODING	ascii	str
SEED	1028862084	int
HPXNSIDE	64	int
HPXNEST	T	bool

Required Data Table Columns

Name	Type	Units	Description
BRICKID	int32
BRICKNAME	char[8]
BRICK_OBJID	int32
RA	float64
DEC	float64
FLUX_G	float32
FLUX_R	float32
FLUX_Z	float32
FLUX_W1	float32
FLUX_W2	float32
MW_TRANSMISSION_G	float32
MW_TRANSMISSION_R	float32
MW_TRANSMISSION_Z	float32
MW_TRANSMISSION_W1	float32
MW_TRANSMISSION_W2	float32
PSFDEPTH_G	float32
PSFDEPTH_R	float32
PSFDEPTH_Z	float32
GALDEPTH_G	float32
GALDEPTH_R	float32
GALDEPTH_Z	float32
PSFDEPTH_W1	float32
PSFDEPTH_W2	float32
SHAPEDEV_R	float32
SHAPEDEV_E1	float32
SHAPEDEV_E2	float32
SHAPEEXP_R	float32
SHAPEEXP_E1	float32
SHAPEEXP_E2	float32
SUBPRIORITY	float64
TARGETID	int64
DESI_TARGET	int64
BGS_TARGET	int64
MWS_TARGET	int64
HPXPIXEL	int64
OBSCONDITIONS	int64

Notes and Examples

• Future versions will include IVAR columns