desi-tiles

Summary:: The DESI footprint, described in terms of tiles. ECSV versions of this file might also be present, lacking vector-valued columns (BRIGHT*).
Naming Convention:: desi-tiles.fits
Regex:: desi-tiles\.fits
File Type:: FITS, 2 MB

Contents

Number	EXTNAME	Type	Contents
HDU0	PRIMARY	IMAGE	Empty Header
HDU1	TILES	BINTABLE	Tile data

EXTNAME = PRIMARY

This HDU has no non-standard required keywords.

Empty HDU.

EXTNAME = TILES

Pre-defined DESI tile locations on the sky (i.e. telescope pointings)

KEY	Example Value	Type	Comment
NAXIS1	114	int	length of dimension 1
NAXIS2	57620	int	length of dimension 2

Name	Type	Units	Description
tileid	int32		Unique tile ID
ra	float64	deg	Right ascension
dec	float64	deg	Declination
pass	int16		DESI layer
in_desi	int16		1=within DESI footprint; 0=outside’
ebv_med	float32	mag	Median Galactic E(B-V) extinction in tile
airmass	float32		Airmass if observed at hour angle 15 deg
star_density	float32	deg^-2	Median number density of Gaia stars brighter than 19.5 mag in tile
exposefac	float32		Multiplicative exposure time factor from airmass and E(B-V)
program	char[6]		DARK, GRAY, BRIGHT, or EXTRA
obsconditions	int32		1 for DARK, 2 for GRAY, 4 for BRIGHT, 0 for EXTRA
brightra	float64[3]	deg	RAs of 3 brightest Tycho-2 stars in tile
brightdec	float64[3]	deg	Decs of 3 brightest Tycho-2 stars in tile
brightvtmag	float32[3]	mag	V_T magnitudes of 3 brightest Tycho-2 stars in tile
centerid	int32		Unique tile ID of pass 0 tile corresponding to this tile