fluxcalibaverage-ARM-NIGHT.fits
- Summary:
Flux calibration file contains an average calibration model for a given camera including airmass and seeing dependencies.
- Naming Convention:
fluxcalibaverage-{ARM}-{NIGHT}.fits, where where{ARM}is one of the spectrograph arms (e.g.b) and{NIGHT}is a date in YYYYMMDD format.- Regex:
fluxcalibaverage-[brz]-[0-9]{8}\.fits- File Type:
FITS, 84 KB
The model is parameterized as
calibration_model(lambda) = average_cal(lambda) * 10^( -0.4*( (seeing-pivot_seeing)*seeing_term(lambda) + (airmass-pivot_airmass)*atm_ext(lambda) ))
calib_flux [1e-17 erg/s/cm2/Angstrom] = uncalib_flux [counts/Angstrom] / (calibration_model * exptime [s])
Contents
Number |
EXTNAME |
Type |
Contents |
|---|---|---|---|
FLUXCALIB |
IMAGE |
Average flux calibration |
|
ATERM |
IMAGE |
Airmass dependent term |
|
STERM |
IMAGE |
Seeing dependent term |
|
WAVELENGTH |
IMAGE |
Wavelength grid |
|
ATERM_ERR |
IMAGE |
Uncertainty on airmass dependent term |
|
STERM_ERR |
IMAGE |
Uncertainty on seeing dependent term |
|
FFRACFLUX_WAVE |
IMAGE |
TODO: Description needed. |
FITS Header Units
HDU0
EXTNAME = FLUXCALIB
Average flux calibration model such that calibrated flux = uncalibrated photons / model.
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2380 |
int |
|
BUNIT |
10**+17 cm2 count s / erg |
str |
i.e. (elec/A) / (1e-17 erg/s/cm2/A) |
CHECKSUM |
2pfC2ofA2ofA2ofA |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
3135063907 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2380]
HDU1
EXTNAME = ATERM
Atmospheric extinction term
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2380 |
int |
|
PAIRMASS |
1.132032318244172 |
float |
pivot airmass (airmass of average calib.) |
CHECKSUM |
Xd3dYd0bXd0bXd0b |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
1519080666 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2380]
HDU2
EXTNAME = STERM
Seeing term
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2380 |
int |
|
PSEEING |
1.075342118740081 |
float |
pivot seeing (seeing of average calib.), FWHM arcsec |
CHECKSUM |
IOTaKNRTINRZINRZ |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
1211437529 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2380]
HDU3
EXTNAME = WAVELENGTH
Wavelengths at which the flux calibration model is evaluated.
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2380 |
int |
|
BUNIT |
Angstrom |
str |
|
CHECKSUM |
CbCQFZ9OCaAOCY9O |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
3517056679 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2380]
HDU4
EXTNAME = ATERM_ERR
Uncertainty on atmospheric extinction term
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2380 |
int |
|
CHECKSUM |
fCmKhBkHfBkHfBkH |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
984665518 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2380]
HDU5
EXTNAME = STERM_ERR
Uncertainty on seeing dependent term
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2380 |
int |
|
CHECKSUM |
LaNJNZNJLaNJLYNJ |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
803867299 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2380]
HDU6
EXTNAME = FFRACFLUX_WAVE
TODO: Description needed.
Required Header Keywords
Required Header Keywords Table
KEY |
Example Value |
Type |
Comment |
|---|---|---|---|
NAXIS1 |
2751 |
int |
|
MDSEEING |
0.8553508780470 |
float |
TODO: Description needed. |
MDFFRACF |
0.7200142212446 |
float |
TODO: Description needed. |
FACWPOW |
-0.25 |
float |
TODO: Description needed. |
FSTNIGHT |
20201214 |
int |
TODO: Description needed. |
CHECKSUM |
LaNJNZNJLaNJLYNJ |
str |
HDU checksum updated 2018-11-27T11:46:41 |
DATASUM |
803867299 |
str |
data unit checksum updated 2018-11-27T11:46:41 |
Data: FITS image [float32, 2751]
Notes and Examples
File produced by the desispec script desi_average_flux_calibration. Used by QuickLook and the off-line calibration.