priminfo

Summary:

priminfo files include a binary table containing matches between secondary targets and DESI primary targets in a (nested) HEALPixel.

Naming Convention:

PHASEtargets-no-obscon-hp-HP.fits, where PHASE is sv1 or sv3 for the corresponding survey, but empty for main and HP is the HEALPixel covered at the (nested) HEALPixel nside included in the file header as FILENSID (e.g. 11).

Regex:

(sv1|sv3|)targets-no-obscon-hp-?[0-9]+\.fits

File Type:

FITS, 12 KB - 9.8 MB

Contents

Number	EXTNAME	Type	Contents
HDU0		IMAGE	Empty
HDU1	TARGETS	SCND_TARG	Matches between primary and secondary targets

FITS Header Units

HDU0

This HDU has no non-standard required keywords.

Empty HDU.

HDU1

EXTNAME = SCND_TARG

Matches between primary and secondary targets

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	130	int	width of table in bytes
NAXIS2	30444	int	number of rows in table
SURVEY	“main”	str	svX for SV, main for Main Survey

Required Data Table Columns

Name	Type	Units	Description
RA	float64	deg	Right ascension
DEC	float64	deg	Declination
PMRA	float32	mas / yr	Proper motion in the RA direction
PMDEC	float32	mas / yr	Proper motion in the Dec direction
REF_EPOCH	float32	yr	Astrometric reference epoch. Typically 2015.5.
OVERRIDE	logical		If True do not match to and accept an existing primary target. Instead, always generate a new TARGETID
FLUX_G	float32	nanomaggy	LS flux from tractor input (g)
FLUX_R	float32	nanomaggy	LS flux from tractor input (r)
FLUX_Z	float32	nanomaggy	LS flux from tractor input (z)
PARALLAX	float32	mas	Reference catalog parallax
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
GAIA_ASTROMETRIC_EXCESS_NOISE	float32		Gaia astrometric excess noise
TARGETID	int64		Unique targeting ID
DESI_TARGET	int64		DESI (dark time program) target selection bitmask
SCND_TARGET	int64		SCND (secondary program) target selection bitmask
SCND_ORDER	int32		Row in which this target appeared in the input secondary target file
PRIORITY_INIT	int64		Initial priority for target calculated across target selection bitmasks and OBSCONDITIONS
SUBPRIORITY	float64		Random subpriority [0-1] to break assignment ties
NUMOBS_INIT	int64		Initial number of observations for target calculated across target selection bitmasks and OBSCONDITIONS
OBSCONDITIONS	int64		Flag target to be observed in combinations of dark/bright observing layer
SCND_TARGET_INIT	int64		Duplication of SCND_TARGET column (used for internal bookkeeping)
PRIM_MATCH	logical		True if a secondary target matches a primary target

Notes

The general user will likely not find the priminfo files useful. They are generated for internal bookkeeping to track whether a secondary target is a “standalone” secondary target or is instead allowed to be merged with a DESI primary target.