fluxcalib-CAMERA.fits¶
- Summary:
Flux calibration file contains an average calibration model for a given camera including airmass and seeing dependencies.
- Naming Convention:
fluxcalib-{CAMERA}.fits, where where{CAMERA}is one of the spectrograph cameras (e.g.z1).- Regex:
fluxcalib-{brz][0-9].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 |
FITS Header Units¶
HDU0¶
EXTNAME = FLUXCALIB
Average flux calibration model such that calibrated flux = uncalibrated photons / model.
Required Header Keywords¶
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¶
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¶
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¶
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¶
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¶
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]
Notes and Examples¶
File produced by the desispec script desi_average_flux_calibration. Used by QuickLook and the off-line calibration.