coadd-SURVEY-PROGRAM-PIXNUM.fits

Summary:

This holds the calibrated coadded spectra organized by healpix location on the sky.

Naming Convention:

coadd-SURVEY-PROGRAM-PIXNUM.fits, where SURVEY is e.g. main or sv1, PROGRAM is e.g. bright or dark and PIXNUM is the HEALPixel number.

Regex:

coadd-(cmx|main|special|sv1|sv2|sv3)-(backup|bright|dark|other)-[0-9]+\.fits

File Type:

FITS, 219 MB

This file follows nearly the same format as the spectra files, except there is one entry per target instead of one entry per exposure per target, and the FIBERMAP replaces some exposure-specific columns with summary columns, e.g. NIGHT becomes FIRST_NIGHT, LAST_NIGHT, and NUM_NIGHT.

Contents

Number	EXTNAME	Type	Contents
HDU00		IMAGE	Keywords only
HDU01	FIBERMAP	BINTABLE	fibermap table
HDU02	EXP_FIBERMAP	BINTABLE	Per-exposure entries from input fibermaps
HDU03	B_WAVELENGTH	IMAGE	Wavelength array of b-channel spectra
HDU04	B_FLUX	IMAGE	Flux of b-channel spectra
HDU05	B_IVAR	IMAGE	Inverse variance of b-channel spectra
HDU06	B_MASK	BINTABLE	Mask of b-channel spectra
HDU07	B_RESOLUTION	IMAGE	Resolution matrices of b-channel spectra
HDU08	R_WAVELENGTH	IMAGE	Wavelength array of r-channel spectra
HDU09	R_FLUX	IMAGE	Flux of r-channel spectra
HDU10	R_IVAR	IMAGE	Inverse variance of r-channel spectra
HDU11	R_MASK	BINTABLE	Mask of r-channel spectra
HDU12	R_RESOLUTION	IMAGE	Resolution matrices of r-channel spectra
HDU13	Z_WAVELENGTH	IMAGE	Wavelength array of z-channel spectra
HDU14	Z_FLUX	IMAGE	Flux of z-channel spectra
HDU15	Z_IVAR	IMAGE	Inverse variance of z-channel spectra
HDU16	Z_MASK	BINTABLE	Mask of z-channel spectra
HDU17	Z_RESOLUTION	IMAGE	Resolution matrices of z-channel spectra
HDU18	SCORES	BINTABLE	scores table

Note: the above is the order in which these HDUs appear in DESI spectroscopic pipeline output, but the order is arbitrary and they should be read by name not by number.

FITS Header Units

HDU00

HEALPixel keywords.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
SPGRP	healpix	str	Method of grouping spectra (always healpix for this file)
SPGRPVAL	38863	int	Healpix number
HPXPIXEL	38863	int	Healpix number
HPXNSIDE	64	int	Healpix nside
HPXNEST	True	str	Healpix nested? (vs. ring)
SURVEY	sv3	str	DESI survey (sv1, sv3, main…)
PROGRAM	dark	str	DESI program (dark, bright, …)
CHECKSUM	96ZDB6YB96YBA6YB	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	0	str	data unit checksum updated 2021-07-20T01:03:03
FIBERMIN	-513	int
INFIL000	spectra-sv1-dark-38863.fits	str
LONGSTRN	OGIP 1.0	str

Empty HDU.

HDU01

EXTNAME = FIBERMAP

Fibermap information combining the targeting photometry and metadata, and fiberassign requested positions. In the coadds, this HDU contains only the information that remains applicable to coadded spectra, e.g. the target flux values. Values that are only meaningful per-exposure (e.g. FIBER_X, FIBER_Y) are contained in the separate EXP_FIBERMAP HDU.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	341	int	Width of table in bytes
NAXIS2	514	int	Number of targets
ENCODING	ascii	str
LONGSTRN	OGIP 1.0	str
CHECKSUM	4aNU7WKR4aKR4UKR	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	4121667036	str	data unit checksum updated 2021-07-20T01:03:03

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique DESI target ID
COADD_FIBERSTATUS	int32		bitwise-AND of input FIBERSTATUS
TARGET_RA	float64	deg	Barycentric right ascension in ICRS
TARGET_DEC	float64	deg	Barycentric declination in ICRS
PMRA	float32	mas yr^-1	proper motion in the +RA direction (already including cos(dec))
PMDEC	float32	mas yr^-1	Proper motion in the +Dec direction
REF_EPOCH	float32	yr	Reference epoch for Gaia/Tycho astrometry. Typically 2015.5 for Gaia
FA_TARGET	int64		Targeting bit internally used by fiberassign (linked with FA_TYPE)
FA_TYPE	binary		Fiberassign internal target type (science, standard, sky, safe, suppsky)
OBJTYPE	char[3]		Object type: TGT, SKY, NON, BAD
SUBPRIORITY	float64		Random subpriority [0-1) to break assignment ties
OBSCONDITIONS	int32		Bitmask of allowed observing conditions
RELEASE	int16		Imaging surveys release ID
BRICKID	int32		Brick ID from tractor input
BRICK_OBJID	int32		Imaging Surveys OBJID on that brick
MORPHTYPE	char[4]		Imaging Surveys morphological type from Tractor
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)
FLUX_IVAR_G	float32	nanomaggy^-2	Inverse variance of FLUX_G (AB)
FLUX_IVAR_R	float32	nanomaggy^-2	Inverse variance of FLUX_R (AB)
FLUX_IVAR_Z	float32	nanomaggy^-2	Inverse variance of FLUX_Z (AB)
MASKBITS	int16		Bitwise mask from the imaging indicating potential issue or blending
REF_ID	int64		Tyc1*1,000,000+Tyc2*10+Tyc3 for Tycho-2; “sourceid” for Gaia DR2
REF_CAT	char[2]		Reference catalog source for star: “T2” for Tycho-2, “G2” for Gaia DR2, “L2” for the SGA, empty otherwise
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
PARALLAX	float32	mas	Reference catalog parallax
BRICKNAME	char[8]		Brick name from tractor input
EBV	float32	mag	Galactic extinction E(B-V) reddening from SFD98
FLUX_W1	float32	nanomaggy	WISE flux in W1 (AB)
FLUX_W2	float32	nanomaggy	WISE flux in W2 (AB)
FLUX_IVAR_W1	float32	nanomaggy^-2	Inverse variance of FLUX_W1 (AB)
FLUX_IVAR_W2	float32	nanomaggy^-2	Inverse variance of FLUX_W2 (AB)
FIBERFLUX_G	float32	nanomaggy	Predicted g-band flux within a fiber of diameter 1.5 arcsec from this object in 1 arcsec Gaussian seeing
FIBERFLUX_R	float32	nanomaggy	Predicted r-band flux within a fiber of diameter 1.5 arcsec from this object in 1 arcsec Gaussian seeing
FIBERFLUX_Z	float32	nanomaggy	Predicted z-band flux within a fiber of diameter 1.5 arcsec from this object in 1 arcsec Gaussian seeing
FIBERTOTFLUX_G	float32	nanomaggy	Predicted g-band flux within a fiber of diameter 1.5 arcsec from all sources at this location in 1 arcsec Gaussian seeing
FIBERTOTFLUX_R	float32	nanomaggy	Predicted r-band flux within a fiber of diameter 1.5 arcsec from all sources at this location in 1 arcsec Gaussian seeing
FIBERTOTFLUX_Z	float32	nanomaggy	Predicted z-band flux within a fiber of diameter 1.5 arcsec from all sources at this location in 1 arcsec Gaussian seeing
SERSIC	float32		Power-law index for the Sersic profile model (MORPHTYPE=”SER”)
SHAPE_R	float32	arcsec	Half-light radius of galaxy model (>0)
SHAPE_E1	float32		Ellipticity component 1 of galaxy model for galaxy type MORPHTYPE
SHAPE_E2	float32		Ellipticity component 2 of galaxy model for galaxy type MORPHTYPE
PHOTSYS	char[1]		‘N’ for the MzLS/BASS photometric system, ‘S’ for DECaLS
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
SV1_DESI_TARGET [1]	int64		DESI (dark time program) target selection bitmask for SV1
SV1_BGS_TARGET [1]	int64		BGS (bright time program) target selection bitmask for SV1
SV1_MWS_TARGET [1]	int64		MWS (bright time program) target selection bitmask for SV1
SV1_SCND_TARGET [1]	int64		Secondary target selection bitmask for SV1
DESI_TARGET	int64		DESI (dark time program) target selection bitmask
BGS_TARGET	int64		BGS (Bright Galaxy Survey) target selection bitmask
MWS_TARGET	int64		Milky Way Survey targeting bits
SCND_TARGET	int64		Target selection bitmask for secondary programs
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
COADD_NUMEXP	int16		Number of exposures in coadd
COADD_EXPTIME	float32	s	Summed exposure time for coadd
COADD_NUMNIGHT	int16		Number of nights in coadd
COADD_NUMTILE	int16		Number of tiles in coadd
MEAN_DELTA_X	float32	mm	Mean (over exposures) fiber difference requested - actual CS5 X location on focal plane
RMS_DELTA_X	float32	mm	RMS (over exposures) of the fiber difference between measured and requested CS5 X location on focal plane
MEAN_DELTA_Y	float32	mm	Mean (over exposures) fiber difference requested - actual CS5 Y location on focal plane
RMS_DELTA_Y	float32	mm	RMS (over exposures) of the fiber difference between measured and requested CS5 Y location on focal plane
MEAN_FIBER_RA	float64	deg	Mean (over exposures) RA of actual fiber position
STD_FIBER_RA	float32	arcsec	Standard deviation (over exposures) of RA of actual fiber position
MEAN_FIBER_DEC	float64	deg	Mean (over exposures) DEC of actual fiber position
STD_FIBER_DEC	float32	arcsec	Standard deviation (over exposures) of DEC of actual fiber position
MEAN_PSF_TO_FIBER_SPECFLUX	float32		Mean of input exposures fraction of light from point-like source captured by 1.5 arcsec diameter fiber given atmospheric seeing

[1] (1,2,3,4)

Optional

HDU02

EXTNAME = EXP_FIBERMAP

Fibermap entries that only apply to individual exposures, not to a coadd. This table has one row per input target per exposure. Also see the FIBERMAP HDU for coadded fibermap quantities with one row per target.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	162	int	Width of table in bytes
NAXIS2	7112	int	Number of input target-exposures
ENCODING	ascii	str
CHECKSUM	g3Nmh2Nlg2Nlg2Nl	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	3607867694	str	data unit checksum updated 2021-07-20T01:03:03

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique DESI target ID
PRIORITY	int32		Target current priority
SUBPRIORITY	float64		Random subpriority [0-1) to break assignment ties
NIGHT	int32
EXPID	int32		DESI Exposure ID number
MJD	float64		Modified Julian Date when shutter was opened for this exposure
TILEID	int32		Unique DESI tile ID
EXPTIME	float64	s	Length of time shutter was open
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]
FIBERSTATUS	int32		Fiber status mask. 0=good
FIBERASSIGN_X	float32	mm	Fiberassign expected CS5 X location on focal plane
FIBERASSIGN_Y	float32	mm	Fiberassign expected CS5 Y location on focal plane
LAMBDA_REF	float32	Angstrom	Requested wavelength at which targets should be centered on fibers
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
NUM_ITER	int64		Number of positioner iterations
FIBER_X	float64	mm	CS5 X location requested by PlateMaker
FIBER_Y	float64	mm	CS5 Y location requested by PlateMaker
DELTA_X	float64	mm	CS5 X requested minus actual position
DELTA_Y	float64	mm	CS5 Y requested minus actual position
FIBER_RA	float64	deg	RA of actual fiber position
FIBER_DEC	float64	deg	DEC of actual fiber position
PSF_TO_FIBER_SPECFLUX	float64		fraction of light from point-like source captured by 1.5 arcsec diameter fiber given atmospheric seeing

HDU03

EXTNAME = B_WAVELENGTH

Wavelength[nwave] array in Angstroms of b-channel spectra

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2751	int	Number of wavelength bins
BUNIT	Angstrom	str
CHECKSUM	9FJDF9H99CHCC9H9	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	979185614	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float64, 2751]

HDU04

EXTNAME = B_FLUX

Flux[nspec,nwave] array in 1e-17 erg/(s cm2 Angstrom) of b-channel spectra

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2751	int	Number of wavelength bins
NAXIS2	514	int	Number of spectra
BUNIT	10**-17 erg/(s cm2 Angstrom)	str
CHECKSUM	KdcnKccnKccnKccn	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	1454063034	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float32, 2751x514]

HDU05

EXTNAME = B_IVAR

Inverse variance of b-channel flux array

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2751	int	Number of wavelength bings
NAXIS2	514	int	Number of spectra
BUNIT	10**+34 (s2 cm4 Angstrom2) / erg2	str
CHECKSUM	1AE635E61AE613E6	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	2902189966	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float32, 2751x514]

HDU06

EXTNAME = B_MASK

Mask[nspec,nwave] of b-channel flux array; 0=good. See the bitmask documentation page for the definition of the bits.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2751	int	Number of wavelength bins
NAXIS2	514	int	Number of spectra
BSCALE	1	int
BZERO	2147483648	int
CHECKSUM	78fA97f677fA77f3	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	707110	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [int32, 2751x514]

HDU07

EXTNAME = B_RESOLUTION

Resolution matrix stored as diagonals of a 3D sparse matrix. See the frame file RESOLUTION documentation for how these are interpreted and used.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2751	int	Number of wavelength bins
NAXIS2	11	int	Number of diagonals
NAXIS3	514	int	Number of spectra
CHECKSUM	4q1B4o094o0A4o09	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	1510900028	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float32, 2751x11x514]

A sparse resolution matrix may be created for spectrum i with:

from desispec.resolution import Resolution
R = Resolution(data[i])

Or using lower-level scipy.sparse matrices:

import scipy.sparse
import numpy as np
nspec, ndiag, nwave = data.shape
offsets = ndiag//2 - np.arange(ndiag, dtype=int)
R = scipy.sparse.dia_matrix((data[i], offsets), shape=(nwave, nwave))

HDU08

EXTNAME = R_WAVELENGTH

Wavelength[nwave] array in Angstroms of r-channel spectra

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2326	int	Number of wavelength bins
BUNIT	Angstrom	str
CHECKSUM	9JTAFHQ79HQACHQ7	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	456732359	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float64, 2326]

HDU09

EXTNAME = R_FLUX

Flux[nspec,nwave] array in 1e-17 erg/(s cm2 Angstrom) of r-channel spectra

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2326	int	Number of wavelength bins
NAXIS2	514	int	Number of spectra
BUNIT	10**-17 erg/(s cm2 Angstrom)	str
CHECKSUM	PCCbR99bPACbP99b	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	54356891	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float32, 2326x514]

HDU10

EXTNAME = R_IVAR

Inverse variance of the R_FLUX HDU.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2326	int
NAXIS2	514	int
BUNIT	10**+34 (s2 cm4 Angstrom2) / erg2	str
CHECKSUM	GeBDGZ9DGbADGZ7D	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	789948970	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [float32, 2326x514]

HDU11

EXTNAME = R_MASK

Mask[nspec,nwave] of r-channel flux array. 0==good. See the bitmask documentation page for the definition of the bits.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2326	int	Number of wavelengths
NAXIS2	514	int	Number of spectra
BSCALE	1	int
BZERO	2147483648	int
CHECKSUM	T5gdV3dcT3dcT3dc	str	HDU checksum updated 2021-07-20T01:03:03
DATASUM	598689	str	data unit checksum updated 2021-07-20T01:03:03

Data: FITS image [int32, 2326x514]

HDU12

EXTNAME = R_RESOLUTION

Diagonals of r-channel resolution matrix.

See B_RESOLUTION HDU for description of the format.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2326	int	Number of wavelengths
NAXIS2	11	int	Number of diagonals
NAXIS3	514	int	Number of spectra
CHECKSUM	DkAIDj3GDjAGDj3G	str	HDU checksum updated 2021-07-20T01:03:04
DATASUM	1927301622	str	data unit checksum updated 2021-07-20T01:03:04

Data: FITS image [float32, 2326x11x514]

HDU13

EXTNAME = Z_WAVELENGTH

Wavelength[nwave] array in Angstroms of z-channel spectra

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2881	int	Number of wavelengths
BUNIT	Angstrom	str
CHECKSUM	iaWMkYVMiaVMiYVM	str	HDU checksum updated 2021-07-20T01:03:04
DATASUM	3106662670	str	data unit checksum updated 2021-07-20T01:03:04

Data: FITS image [float64, 2881]

HDU14

EXTNAME = Z_FLUX

Flux[nspec,nwave] array in 1e-17 erg/(s cm2 Angstrom) of z-channel spectra

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2881	int	Number of wavelengths
NAXIS2	514	int	Number of spectra
BUNIT	10**-17 erg/(s cm2 Angstrom)	str
CHECKSUM	0aea1VdZ0Zda0ZdY	str	HDU checksum updated 2021-07-20T01:03:04
DATASUM	1889497861	str	data unit checksum updated 2021-07-20T01:03:04

Data: FITS image [float32, 2881x514]

HDU15

EXTNAME = Z_IVAR

Inverse variance of z-channel flux array

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2881	int	Number of wavelengths
NAXIS2	514	int	Number of spectra
BUNIT	10**+34 (s2 cm4 Angstrom2) / erg2	str
CHECKSUM	ni6Dpi3Cni3Cni3C	str	HDU checksum updated 2021-07-20T01:03:04
DATASUM	105099897	str	data unit checksum updated 2021-07-20T01:03:04

Data: FITS image [float32, 2881x514]

HDU16

EXTNAME = Z_MASK

Mask[nspec,nwave] of z-channel flux array. 0==good. See the bitmask documentation page for the definition of the bits.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2881	int	Number of wavelengths
NAXIS2	514	int	Number of spectra
BSCALE	1	int
BZERO	2147483648	int
CHECKSUM	X6iYY4gYX4gYX4gY	str	HDU checksum updated 2021-07-20T01:03:04
DATASUM	740483	str	data unit checksum updated 2021-07-20T01:03:04

Data: FITS image [int32, 2881x514]

HDU17

EXTNAME = Z_RESOLUTION

Diagonals of z-channel resolution matrix.

See B_RESOLUTION HDU for description of the format.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	2881	int	Number of wavelengths
NAXIS2	11	int	Number of diagonals
NAXIS3	514	int	Number of spectra
CHECKSUM	oocZpnbYonbYonbY	str	HDU checksum updated 2021-07-20T01:03:04
DATASUM	1564215354	str	data unit checksum updated 2021-07-20T01:03:04

Data: FITS image [float32, 2881x11x514]

HDU18

EXTNAME = SCORES

Scores / metrics measured from the spectra for use in QA and systematics studies. These are coadded from the input cframe SCORES HDU files.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	172	int	Width of table in bytes
NAXIS2	514	int	Number of spectra
ENCODING	ascii	str
CHECKSUM	XQAAZP89XPAAXP79	str	HDU checksum updated 2021-07-20T01:03:05
DATASUM	3357773203	str	data unit checksum updated 2021-07-20T01:03:05

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique DESI target ID
INTEG_COADD_FLUX_B	float32		integ. flux in wave. range 4000,5800A
MEDIAN_COADD_FLUX_B	float32		median flux in wave. range 4000,5800A
MEDIAN_COADD_SNR_B	float32		median SNR/sqrt(A) in wave. range 4000,5800A
INTEG_COADD_FLUX_R	float32		integ. flux in wave. range 5800,7600A
MEDIAN_COADD_FLUX_R	float32		median flux in wave. range 5800,7600A
MEDIAN_COADD_SNR_R	float32		median SNR/sqrt(A) in wave. range 5800,7600A
INTEG_COADD_FLUX_Z	float32		integ. flux in wave. range 7600,9800A
MEDIAN_COADD_FLUX_Z	float32		median flux in wave. range 7600,9800A
MEDIAN_COADD_SNR_Z	float32		median SNR/sqrt(A) in wave. range 7600,9800A
TSNR2_GPBDARK_B	float32		template (S/N)^2 for dark targets in guider pass band on B
TSNR2_ELG_B	float32		ELG B template (S/N)^2
TSNR2_GPBBRIGHT_B	float32		template (S/N)^2 for bright targets in guider pass band on B
TSNR2_LYA_B	float32		LYA B template (S/N)^2
TSNR2_BGS_B	float32		BGS B template (S/N)^2
TSNR2_GPBBACKUP_B	float32		GPBBACKUP B template (S/N)^2
TSNR2_QSO_B	float32		QSO B template (S/N)^2
TSNR2_LRG_B	float32		LRG B template (S/N)^2
TSNR2_GPBDARK_R	float32		template (S/N)^2 for dark targets in guider pass band on R
TSNR2_ELG_R	float32		ELG R template (S/N)^2
TSNR2_GPBBRIGHT_R	float32		template (S/N)^2 for bright targets in guider pass band on R
TSNR2_LYA_R	float32		LYA R template (S/N)^2
TSNR2_BGS_R	float32		BGS R template (S/N)^2
TSNR2_GPBBACKUP_R	float32		GPBBACKUP R template (S/N)^2
TSNR2_QSO_R	float32		QSO R template (S/N)^2
TSNR2_LRG_R	float32		LRG R template (S/N)^2
TSNR2_GPBDARK_Z	float32		template (S/N)^2 for dark targets in guider pass band on Z
TSNR2_ELG_Z	float32		ELG Z template (S/N)^2
TSNR2_GPBBRIGHT_Z	float32		template (S/N)^2 for bright targets in guider pass band on Z
TSNR2_LYA_Z	float32		LYA Z template (S/N)^2
TSNR2_BGS_Z	float32		BGS Z template (S/N)^2
TSNR2_GPBBACKUP_Z	float32		GPBBACKUP Z template (S/N)^2
TSNR2_QSO_Z	float32		QSO Z template (S/N)^2
TSNR2_LRG_Z	float32		LRG Z template (S/N)^2
TSNR2_GPBDARK	float32		template (S/N)^2 for dark targets in guider pass band
TSNR2_ELG	float32		ELG template (S/N)^2 summed over B,R,Z
TSNR2_GPBBRIGHT	float32		template (S/N)^2 for bright targets in guider pass band
TSNR2_LYA	float32		LYA template (S/N)^2 summed over B,R,Z
TSNR2_BGS	float32		BGS template (S/N)^2 summed over B,R,Z
TSNR2_GPBBACKUP	float32		GPBBACKUP template (S/N)^2 summed over B,R,Z
TSNR2_QSO	float32		QSO template (S/N)^2 summed over B,R,Z
TSNR2_LRG	float32		LRG template (S/N)^2 summed over B,R,Z

Notes and Examples

Coadd files can be read and interpreted using the same code examples shown in the “Notes and Examples” section of the spectra files documentation.

The format supports arbitrary channel (camera) names as long as for each channel {X} there is a set of HDUs named {X}_WAVELENGTH, {X}_FLUX, {X}_IVAR, {X}_MASK, {X}_RESOLUTION.

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.

For targets with a non-zero proper motion, FIBER_RA and FIBER_DEC refer to the position at the reference epoch (but note that the proper-motion correction has been applied at the time of the observation, it is just not recorded in FIBER_RA and FIBER_DEC).