TILEID-scnd.fits

Summary:

This file contains the secondary targets covered by the tile disk-footprint.

Naming Convention:

{TILEID}-scnd.fits, where {TILEID} is the zero-padded, 6-digit TILED.

Regex:

[0-9]{6}-scnd\.fits

File Type:

FITS, 1 MB

Contents

Number	EXTNAME	Type	Contents
HDU0		IMAGE	Empty HDU
HDU1	TARGETS	BINTABLE	Secondary targets covered by the tile disk-footprint.

FITS Header Units

HDU0

This HDU has no non-standard required keywords.

Empty HDU.

HDU1

EXTNAME = TARGETS

Secondary targets covered by the tile disk-footprint: those are read from the MTL ledgers and desitarget catalogs and provided as input to fiberassign.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	275	int	width of table in bytes
NAXIS2	4751	int	number of rows in table
SURVEY	main	str
RESOLVE	T	bool
MASKBITS	T	bool
BACKUP	F	bool
NOSEC	F	bool
DR	None	Unknown

Required Data Table Columns

Name	Type	Units	Description
FLUX_G	float32	nanomaggy	Flux in the Legacy Survey g-band (AB)
FLUX_R	float32	nanomaggy	Flux in the Legacy Survey r-band (AB)
FLUX_Z	float32	nanomaggy	Flux in the Legacy Survey z-band (AB)
GAIA_PHOT_G_MEAN_MAG	float32	mag	Gaia G band magnitude
GAIA_PHOT_BP_MEAN_MAG	float32	mag	Gaia BP band magnitude
GAIA_PHOT_RP_MEAN_MAG	float32	mag	Gaia RP band magnitude
TARGETID	int64		Unique DESI target ID
RA	float64	deg	Barycentric Right Ascension in ICRS
DEC	float64	deg	Barycentric declination in ICRS
PMRA	float32	mas / yr	proper motion in the +RA direction (already including cos(dec))
PMDEC	float32	mas / yr	Proper motion in the +Dec direction
REF_EPOCH	float32	yr	Reference epoch for Gaia/Tycho astrometry. Typically 2015.5 for Gaia
PARALLAX	float32	mas	Reference catalog parallax
DESI_TARGET	int64		DESI (dark time program) target selection bitmask
SCND_TARGET	int64		Target selection bitmask for secondary programs
SUBPRIORITY	float64		Random subpriority [0-1) to break assignment ties
OBSCONDITIONS	int32		Bitmask of allowed observing conditions
PRIORITY_INIT	int64		Target initial priority from target selection bitmasks and OBSCONDITIONS
NUMOBS_INIT	int64		Initial number of observations for target calculated across target selection bitmasks and OBSCONDITIONS
BGS_TARGET	int64		BGS (Bright Galaxy Survey) target selection bitmask
MWS_TARGET	int64		Milky Way Survey targeting bits
NUMOBS_MORE	int64		Number of additional observations needed
NUMOBS	int64		Number of spectroscopic observations (on this specific, single tile)
Z	float64		Redshift measured by Redrock
ZWARN	int64		Redshift warning bitmask from Redrock
ZTILEID	int32		ID of tile that most recently updated target’s state
Z_QN	float64		Redshift measured by QuasarNET using line with highest confidence
IS_QSO_QN	int16		Spectroscopic classification from QuasarNET (1 for a quasar)
DELTACHI2	float64		chi2 difference between first- and second-best redrock template fits
TARGET_STATE	char[30]		Combination of target class and its current observational state
TIMESTAMP	char[25]	s	UTC/ISO time at which the target state was updated
VERSION	char[14]		Tag of desitarget used to create the target catalog
PRIORITY	int64		Target current priority
PLATE_RA	float64	deg	Barycentric Right Ascension in ICRS to be used by PlateMaker
PLATE_DEC	float64	deg	Barycentric Declination in ICRS to be used by PlateMaker
PLATE_REF_EPOCH	float32	yr	Copy of REF_EPOCH to be used by PlateMaker

Notes and Examples

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 fiberassign design step; thus the following columns can have different values than in the desitarget products: TARGET_RA, TARGET_DEC, REF_EPOCH, PLATE_RA, PLATE_DEC, and PLATE_REF_EPOCH.