KPF Data Format
Overview
KPF data products are defined for these data levels:
Level 0 (L0): Raw data products produced by KPF at the W. M. Keck Observatory
2D: Assembled CCD images with minimal processing. This data product is produced by the DRP during processing from L0 to L1 but is not fundamental and is frequently not archived.
Level 1 (L1): Extracted, wavelength-calibrated spectra
Level 2 (L2): Derived data products including cross-correlation functions, radial velocities, and activity indicators
Each of these data levels is a standardized, multi-extension FITS format, and can be read using standard fits tools (e.g., astropy.fits.io) and the KPF-Pipeline.
KPF L0 files follow the naming convention: KP.YYYYMMDD.SSSSS.ss.fits, where YYYYMMDD is a date and SSSSS.ss is the number of decimal seconds after UT midnight corresponding to the start of the exposure. 2D/L1/L2 files have similar file names, but with ‘_2D’, ‘_L1’, or ‘_L2’ before ‘.fits’. For example, KP.YYYYMMDD.SSSSS.ss_2D.fits is a 2D file name.
See the section titled Opening, Examining, and Manipulating KPF Files for a set of tutorials on the various KPF data files.
In addition, the DRP is able to produce WLS Dictionaries that contain detailed diagnostic information about the fits of individual lines, orders, and orderlets for the wavelength solutions. These are described at the bottom of this page.
Data Format of KPF Files
L0 FITS Extensions
Extension Name |
Data Type |
Data Dimension |
Description |
|---|---|---|---|
GREEN_AMP1 |
image |
4110 x 2094 |
CCD image from Green amplifier 1 |
GREEN_AMP2 |
image |
4110 x 2094 |
CCD image from Green amplifier 2 [a] |
RED_AMP1 |
image |
4110 x 2094 |
CCD image from Red amplifier 1 |
RED_AMP2 |
image |
4110 x 2094 |
CCD image from Red amplifier 2 |
CA_HK |
image |
255 x 1024 |
CCD image from Ca H&K Spectrometer |
EXPMETER_SCI |
table |
variable |
Table of Exposure Meter measurements for SCI channel |
EXPMETER_SKY |
table |
variable |
Table of Exposure Meter measurements for SKY channel |
TELEMETRY |
table |
variable |
Table of telemetry measurements |
SOLAR_IRRADIANCE |
table |
variable |
Table of pyrheliometer measurements (for SoCal spectra) |
GUIDER_AVG |
image |
512 x 640 |
Average image from the guide camera |
GUIDER_CUBE_ORIGINS |
table |
variable |
Table of time-series guide camera measurements |
[a] - the example shown above is for two-amplifier mode. When KPF is operated in fast’ read mode, four amplifiers per CCD will be used and there will be a corresponding number of AMP extensions.
2D File FITS Extensions
Extension Name |
Data Type |
Data Dimension |
Description |
|---|---|---|---|
RECEIPT |
table |
variable |
Receipt of DRP processing |
CONFIG |
table |
variable |
Configuration parameters |
GREEN_CCD |
image |
4080 x 4080 |
Assembled Green CCD image with bias/dark correction |
RED_CCD |
image |
4080 x 4080 |
Assembled Red CCD image with bias/dark correction |
CA_HK |
image |
255 x 1024 |
Same as in L0 file |
EXPMETER_SCI |
table |
variable |
Same as in L0 file |
EXPMETER_SKY |
table |
variable |
Same as in L0 file |
TELEMETRY |
table |
variable |
Same as in L0 file |
SOLAR_IRRADIANCE |
table |
variable |
Same as in L0 file |
GUIDER_AVG |
image |
512 x 640 |
Same as in L0 file |
GUIDER_CUBE_ORIGINS |
table |
variable |
Same as in L0 file |
L1 FITS Extensions
Extension Name |
Data Type |
Data Dimension |
Description |
|---|---|---|---|
RECEIPT |
table |
variable |
Receipt of DRP processing |
CONFIG |
table |
variable |
Configuration parameters |
TELEMETRY |
table |
variable |
Table of telemetry measurements |
GREEN_SCI_FLUX1 |
image |
35 x 4080 |
1D spectra for 35 GREEN CCD orders of SCI1 orderlet |
GREEN_SCI_FLUX2 |
image |
35 x 4080 |
1D spectra for 35 GREEN CCD orders of SCI2 orderlet |
GREEN_SCI_FLUX3 |
image |
35 x 4080 |
1D spectra for 35 GREEN CCD orders of SCI3 orderlet |
GREEN_SKY_FLUX |
image |
35 x 4080 |
1D spectra for 35 GREEN CCD orders of SKY orderlet |
GREEN_CAL_FLUX |
image |
35 x 4080 |
1D spectra for 35 GREEN CCD orders of CAL orderlet |
GREEN_SCI_VAR1 |
image |
35 x 4080 |
Variance vs. pixel for GREEN_SCI_FLUX1 |
GREEN_SCI_VAR2 |
image |
35 x 4080 |
Variance vs. pixel for GREEN_SCI_FLUX2 |
GREEN_SCI_VAR3 |
image |
35 x 4080 |
Variance vs. pixel for GREEN_SCI_FLUX3 |
GREEN_SKY_VAR |
image |
35 x 4080 |
Variance vs. pixel for GREEN_SKY_FLUX |
GREEN_CAL_VAR |
image |
35 x 4080 |
Variance vs. pixel for GREEN_CAL_FLUX |
GREEN_SCI_WAVE1 |
image |
35 x 4080 |
Wavelength vs. pixel for GREEN_SCI_FLUX1 |
GREEN_SCI_WAVE2 |
image |
35 x 4080 |
Wavelength vs. pixel for GREEN_SCI_FLUX2 |
GREEN_SCI_WAVE3 |
image |
35 x 4080 |
Wavelength vs. pixel for GREEN_SCI_FLUX3 |
GREEN_SKY_WAVE |
image |
35 x 4080 |
Wavelength vs. pixel for GREEN_SKY_FLUX |
GREEN_CAL_WAVE |
image |
35 x 4080 |
Wavelength vs. pixel for GREEN_CAL_FLUX |
GREEN_TELLURIC |
table |
n/a |
Not used yet (will include telluric spectrum) |
GREEN_SKY |
table |
n/a |
Not used yet (will include modeled sky spectrum) |
RED_SCI_FLUX1 |
image |
32 x 4080 |
1D spectra for 32 RED CCD orders of SCI1 orderlet |
RED_SCI_FLUX2 |
image |
32 x 4080 |
1D spectra for 32 RED CCD orders of SCI2 orderlet |
RED_SCI_FLUX3 |
image |
32 x 4080 |
1D spectra for 32 RED CCD orders of SCI3 orderlet |
RED_SKY_FLUX |
image |
32 x 4080 |
1D spectra for 32 RED CCD orders of SKY orderlet |
RED_CAL_FLUX |
image |
32 x 4080 |
1D spectra for 32 RED CCD orders of CAL orderlet |
RED_SCI_VAR1 |
image |
32 x 4080 |
Variance vs. pixel for RED_SCI_FLUX1 |
RED_SCI_VAR2 |
image |
32 x 4080 |
Variance vs. pixel for RED_SCI_FLUX2 |
RED_SCI_VAR3 |
image |
32 x 4080 |
Variance vs. pixel for RED_SCI_FLUX3 |
RED_SKY_VAR |
image |
32 x 4080 |
Variance vs. pixel for RED_SCI_FLUX |
RED_CAL_VAR |
image |
32 x 4080 |
Variance vs. pixel for RED_SCI_FLUX |
RED_SCI_WAVE1 |
image |
32 x 4080 |
Wavelength vs. pixel for RED_SCI_FLUX1 |
RED_SCI_WAVE2 |
image |
32 x 4080 |
Wavelength vs. pixel for RED_SCI_FLUX2 |
RED_SCI_WAVE3 |
image |
32 x 4080 |
Wavelength vs. pixel for RED_SCI_FLUX3 |
RED_SKY_WAVE |
image |
32 x 4080 |
Wavelength vs. pixel for RED_SKY_FLUX |
RED_CAL_WAVE |
image |
32 x 4080 |
Wavelength vs. pixel for RED_CAL_FLUX |
RED_TELLURIC |
table |
n/a |
Not used yet (will include telluric spectrum) |
RED_SKY |
table |
n/a |
Not used yet (will include modeled sky spectrum) |
CA_HK_SCI |
image |
6 x 1024 |
1D spectra (6 orders) of SCI in Ca H&K spectrometer |
CA_HK_SKY |
image |
6 x 1024 |
1D spectra (6 orders) of SKY in Ca H&K spectrometer |
CA_HK_SCI_WAVE |
image |
6 x 1024 |
Wavelength vs. pixel for CA_HK_SCI |
CA_HK_SKY_WAVE |
image |
6 x 1024 |
Wavelength vs. pixel for CA_HK_SKY |
BARY_CORR |
table |
67 |
Table of barycentric corrections by spectral order |
L2 FITS Extensions
Extension Name |
Data Type |
Data Dimension |
Description |
|---|---|---|---|
RECEIPT |
table |
variable |
Receipt of DRP processing |
CONFIG |
table |
variable |
Configuration parameters |
TELEMETRY |
table |
variable |
Table of telemetry measurements |
GREEN_CCF |
image |
5 x 52 x 804 |
CCFs (orderlet x order x RV step) for GREEN |
RED_CCF |
image |
5 x 52 x 804 |
CCFs (orderlet x order x RV step) for RED |
GREEN_CCF |
image |
5 x 52 x 804 |
Reweighted CCFs (orderlet x order x RV step) for GREEN |
RED_CCF |
image |
5 x 52 x 804 |
Reweighted CCFs (orderlet x order x RV step) for RED |
RV |
table |
67 |
Table of RVs by spectral order (described below) |
ACTIVITY |
table |
n/a |
Not used yet (will include activity measurements) |
Primary Extension Header Keywords
L0 Primary Extension Header
Most of the important keywords are stored in the primary extension of the Level 0 file, which is written immediately after each KPF exposure.
Keyword |
Value (example) |
Comment |
|---|---|---|
DATE-BEG |
2023-10-22T15:30:01.056733 |
Start of exposure from kpfexpose |
DATE-MID |
2023-10-22T15:32:31.065 |
Halfway point of the exposure (unweighted) |
DATE-END |
2023-10-22T15:35:01.072797 |
End of exposure |
EXPTIME |
300.0 |
Requested exposure time |
ELAPSED |
300.0 |
Actual exposure time |
PROGNAME |
N226 |
Program name from kpfexpose |
OBJECT |
42813 |
Object name |
TARGRA |
06:12:13.80 |
Right ascension [hr] from DCS |
TARGDEC |
-14:38:56.0 |
Declination [deg] from DCS |
TARGEPOC |
2000.0 |
Target epoch from DCS |
TARGEQUI |
2000.0 |
Target equinox from DCS |
TARGPLAX |
14.7 |
Target parallax [arcsec] from DCS |
TARGPMDC |
0.0 |
Target proper motion [arcsec/yr] in declination from DCS |
TARGPMRA |
0.0 |
Target proper motion [s/yr] in right ascension from DCS |
TARGRADV |
81.87 |
Target radial velocity [km/s] |
AIRMASS |
1.26 |
Airmass from DCS |
PARANTEL |
23.58 |
Parallactic angle of the telescope from DCS |
HA |
+01:01:37.22 |
Hour angle |
EL |
52.46 |
Elevation [deg] |
AZ |
204.46 |
Azimuth [deg] |
LST |
07:13:51.02 |
Local sidereal time |
GAIAID |
DR3 2993561629444856960 |
GAIA Target name |
2MASSID |
J06121397-1439002 |
2MASS Target name |
GAIAMAG |
9.28 |
GAIA G band magnitude |
2MASSMAG |
8.06 |
2MASS J band magnitude |
TARGTEFF |
5398.0 |
Target effective temperature (K) |
OCTAGON |
EtalonFiber |
Selected octagon calibration source (not necessarily powered on) |
TRIGTARG |
Green,Red,Ca_HK,ExpMeter,Guide |
Cameras that were sent triggers |
IMTYPE |
Object |
Image Type |
CAL-OBJ |
None |
Calibration fiber source |
SKY-OBJ |
Sky |
Sky fiber source |
SCI-OBJ |
Target |
Science fiber source |
AGITSTA |
Running |
Agitator status |
FIUMODE |
Observing |
FIU operating mode |
TOTCNTS |
1.1299e+08 1.959e+08 1.8185e+08 1.1561e+08 |
Total Exp. Meter counts (DN) - four channels (445.0-551.25, 551.25-657.5, 657.5-763.75, 763.75-870.0 nm) |
TOTCORR |
2.3994e+08 4.1319e+08 3.8088e+08 2.403e+08 |
Total Exp. Meter counts (DN), corrected for dead time - four channels (445.0-551.25, 551.25-657.5, 657.5-763.75, 763.75-870.0 nm) |
ETAV1C1T |
23.990154 |
Etalon Vescent 1 Channel 1 temperature |
ETAV1C2T |
23.79949 |
Etalon Vescent 1 Channel 2 temperature |
ETAV1C3T |
23.599987 |
Etalon Vescent 1 Channel 3 temperature |
ETAV1C4T |
23.900118 |
Etalon Vescent 1 Channel 4 temperature |
ETAV2C3T |
24.000668 |
Etalon Vescent 2 Channel 3 temperature |
2D Primary Extension Header
The 2D file inherits all L0 keywords. Below are additional keywords.
Keyword |
Value (example) |
Comment |
|---|---|---|
DRPTAG |
v2.5.2 |
Git version number of KPF-Pipeline used for processing |
DRPHASH |
‘ccf5f6ebe0c9ae7d43706cc57fed2ecdeb540a17’ |
Git commit hash version of KPF-Pipeline used for processing |
NOTJUNK |
1 |
Quality Control: 1 = not in the list of junk files check; this QC is rerun on L1 and L2 |
DATAPRL0 |
1 |
Quality Control: 1 = L0 data products present with non-zero array sizes |
KWRDPRL0 |
1 |
Quality Control: 1 = L0 expected keywords present |
TIMCHKL0 |
1 |
Quality Control: 1 = consistent times in L0 file |
EMSAT |
1 |
Quality Control: 1 = Exp Meter not saturated; 0 = 2+ reduced EM pixels within 90% of saturation in EM-SCI or EM-SKY |
EMNEG |
1 |
Quality Control: 1 = Exp Meter not negative flux; 0 = 20+ consecutive pixels in summed spectra with negative flux |
RNGREEN1 |
4.85283 |
Read noise for GREEN_AMP1 [e-] (first amplifier region on Green CCD) |
RNGREEN2 |
4.14966 |
Read noise for GREEN_AMP2 [e-] (second amplifier region on Green CCD) |
RNGREEN3 |
4.85283 |
Read noise for GREEN_AMP3 [e-] (third amplifier region on Green CCD) |
RNGREEN4 |
4.14966 |
Read noise for GREEN_AMP4 [e-] (fourth amplifier region on Green CCD) |
RNRED1 |
4.0376 |
Read noise for RED_AMP1 [e-] (first amplifier region on Red CCD) |
RNRED2 |
4.12717 |
Read noise for RED_AMP2 [e-] (second amplifier region on Red CCD) |
RNRED3 |
4.0376 |
Read noise for RED_AMP3 [e-] (third amplifier region on Red CCD) |
RNRED4 |
4.12717 |
Read noise for RED_AMP4 [e-] (fourth amplifier region on Red CCD) |
GREENTRT |
46.804 |
Green CCD read time [sec] |
REDTRT |
46.839 |
Red CCD read time [sec] |
READSPED |
‘regular ‘ |
Categorization of CCD read speed (‘regular’ or ‘fast’) |
FLXREG1G |
1.00 |
Dark current [e-/hr] - Green CCD region 1 - coords = [1690:1990,1690:1990] |
FLXREG2G |
1.00 |
Dark current [e-/hr] - Green CCD region 2 - coords = [1690:1990,2090:2390] |
FLXREG3G |
1.00 |
Dark current [e-/hr] - Green CCD region 3 - coords = [2090:2390,1690:1990] |
FLXREG4G |
1.00 |
Dark current [e-/hr] - Green CCD region 4 - coords = [2090:2390,2090:2390] |
FLXREG5G |
1.00 |
Dark current [e-/hr] - Green CCD region 5 - coords = [80:380,3080:3380] |
FLXREG6G |
1.00 |
Dark current [e-/hr] - Green CCD region 6 - coords = [1690:1990,1690:1990] |
FLXAMP1G |
1.00 |
Dark current [e-/hr] - Green CCD amplifier region 1 - coords = [3700:4000,700:1000] |
FLXAMP2G |
1.00 |
Dark current [e-/hr] - Green CCD amplifier region 2 - coords = [3700:4000,3080:3380] |
FLXCOLLG |
1.00 |
Dark current [e-/hr] - Green CCD collimator-side region = [3700:4000,700:1000] |
FLXECHG |
1.00 |
Dark current [e-/hr] - Green CCD echelle-side region = [3700:4000,700:1000] |
FLXREG1R |
1.00 |
Dark current [e-/hr] - Red CCD region 1 - coords = [1690:1990,1690:1990] |
FLXREG2R |
1.00 |
Dark current [e-/hr] - Red CCD region 2 - coords = [1690:1990,2090:2390] |
FLXREG3R |
1.00 |
Dark current [e-/hr] - Red CCD region 3 - coords = [2090:2390,1690:1990] |
FLXREG4R |
1.00 |
Dark current [e-/hr] - Red CCD region 4 - coords = [2090:2390,2090:2390] |
FLXREG5R |
1.00 |
Dark current [e-/hr] - Red CCD region 5 - coords = [80:380,3080:3380] |
FLXREG6R |
1.00 |
Dark current [e-/hr] - Red CCD region 6 - coords = [1690:1990,1690:1990] |
FLXAMP1R |
1.00 |
Dark current [e-/hr] - Red CCD amplifier region 1 = [3700:4000,700:1000] |
FLXAMP2R |
1.00 |
Dark current [e-/hr] - Red CCD amplifier region 2 = [3700:4000,3080:3380] |
FLXCOLLR |
1.00 |
Dark current [e-/hr] - Red CCD collimator-side region = [3700:4000,700:1000] |
FLXECHR |
1.00 |
Dark current [e-/hr] - Red CCD echelle-side region = [3700:4000,700:1000] |
GDRXRMS |
10.123 |
x-coordinate RMS guiding error in milliarcsec (mas) |
GDRYRMS |
10.123 |
y-coordinate RMS guiding error in milliarcsec (mas) |
GDRRRMS |
10.123 |
r-coordinate RMS guiding error in milliarcsec (mas) |
GDRXBIAS |
0.0010 |
x-coordinate bias guiding error in milliarcsec (mas) |
GDRYBIAS |
0.0010 |
y-coordinate bias guiding error in milliarcsec (mas) |
GDRSEEJZ |
0.450 |
Seeing (arcsec) in J+Z-band from Moffat func fit |
GDRSEEV |
0.450 |
Scaled seeing (arcsec) in V-band from J+Z-band |
MOONSEP |
55.0 |
Separation between Moon and target star (deg) |
SUNALT |
-45.0 |
Altitude of Sun (deg); negative = below horizon |
SKYSCIMS |
0.0000123 |
SKY/SCI flux ratio in main spectrometer scaled from EM data. |
EMSCCT48 |
100000000.1234 |
cumulative EM counts [ADU] in SCI in 445-870 nm |
EMSCCT45 |
100000000.1234 |
cumulative EM counts [ADU] in SCI in 445-551 nm |
EMSCCT56 |
100000000.1234 |
cumulative EM counts [ADU] in SCI in 551-658 nm |
EMSCCT67 |
100000000.1234 |
cumulative EM counts [ADU] in SCI in 658-764 nm |
EMSCCT78 |
100000000.1234 |
cumulative EM counts [ADU] in SCI in 764-870 nm |
EMSKCT48 |
100000000.1234 |
cumulative EM counts [ADU] in SKY in 445-870 nm |
EMSKCT45 |
100000000.1234 |
cumulative EM counts [ADU] in SKY in 445-551 nm |
EMSKCT56 |
100000000.1234 |
cumulative EM counts [ADU] in SKY in 551-658 nm |
EMSKCT67 |
100000000.1234 |
cumulative EM counts [ADU] in SKY in 658-764 nm |
EMSKCT78 |
100000000.1234 |
cumulative EM counts [ADU] in SKY in 764-870 nm |
MEDGRN1 |
3.9642348e+07 |
Median for GREEN_AMP1 [DN] (includes overscan region, excludes NaNs explicitly) |
P16GRN1 |
3.9340188e+07 |
16th-percentile for GREEN_AMP1 [DN] (includes overscan region, excludes NaNs explicitly) |
P84GRN1 |
3.9340188e+07 |
84th-percentile for GREEN_AMP1 [DN] (includes overscan region, excludes NaNs explicitly) |
MEDGRN2 |
3.9642348e+07 |
Median for GREEN_AMP2 [DN] (includes overscan region, excludes NaNs explicitly) |
P16GRN2 |
3.9340188e+07 |
16th-percentile for GREEN_AMP2 [DN] (includes overscan region, excludes NaNs explicitly) |
P84GRN2 |
3.9340188e+07 |
84th-percentile for GREEN_AMP2 [DN] (includes overscan region, excludes NaNs explicitly) |
MEDGRN3 |
3.9642348e+07 |
Median for GREEN_AMP3 [DN] (includes overscan region, excludes NaNs explicitly) |
P16GRN3 |
3.9340188e+07 |
16th-percentile for GREEN_AMP3 [DN] (includes overscan region, excludes NaNs explicitly) |
P84GRN3 |
3.9340188e+07 |
84th-percentile for GREEN_AMP3 [DN] (includes overscan region, excludes NaNs explicitly) |
MEDGRN4 |
3.9642348e+07 |
Median for GREEN_AMP4 [DN] (includes overscan region, excludes NaNs explicitly) |
P16GRN4 |
3.9340188e+07 |
16th-percentile for GREEN_AMP4 [DN] (includes overscan region, excludes NaNs explicitly) |
P84GRN4 |
3.9340188e+07 |
84th-percentile for GREEN_AMP4 [DN] (includes overscan region, excludes NaNs explicitly) |
MEDRED1 |
3.9642348e+07 |
Median for RED_AMP1 [DN] (includes overscan region, excludes NaNs explicitly) |
P16RED1 |
3.9340188e+07 |
16th-percentile for RED_AMP1 [DN] (includes overscan region, excludes NaNs explicitly) |
P84RED1 |
3.9340188e+07 |
84th-percentile for RED_AMP1 [DN] (includes overscan region, excludes NaNs explicitly) |
MEDRED2 |
3.9642348e+07 |
Median for RED_AMP2 [e-] (includes overscan region, excludes NaNs explicitly) |
P16RED2 |
3.9340188e+07 |
16th-percentile for RED_AMP2 [DN] (includes overscan region, excludes NaNs explicitly) |
P84RED2 |
3.9340188e+07 |
84th-percentile for RED_AMP2 [DN] (includes overscan region, excludes NaNs explicitly) |
MEDCAHK |
3.9642348e+07 |
Median for CA_HK_AMP [DN] (includes overscan region, excludes NaNs explicitly) |
P16CAHK |
3.9340188e+07 |
16th-percentile for CA_HK_AMP [DN] (includes overscan region, excludes NaNs explicitly) |
P84CAHK |
3.9340188e+07 |
84th-percentile for CA_HK_AMP [DN] (includes overscan region, excludes NaNs explicitly) |
Keywords related to read noise are only computed for the amplifiers used. In regular read mode, two amplifiers are used (AMP1 and AMP2), while in fast read mode, four amplifiers are used (AMP1, AMP2, AMP3, and AMP4).
Keywords related to dark current (starting with FLX) are only added for 2D files of Dark observations (no illumination and exposure time > 0). The regions for those keywords refer to the CCD coordinates where the dark current measurements were made (using modules/quicklook/arc/analyze_2d.py). The image below (click to enlarge) shows the regions and dark current estimates for a 2D spectrum taken when the dark current was high.
Keywords related to the Guider are only added for 2D files that have Guider data products. Similar for Exposure Meter data products.
Keywords related to L0 amplifier-image statistics (e.g., MEDGRN1) are only added to 2D files. A robust estimator of data dispersion width is sigma = 0.5 * (P84 - P16), equivalent to one standard deviation for normally distributed data.
L1 Primary Extension Header
The L1 file inherits all L0 and 2D keywords. Below are additional important keywords.
Keyword |
Value (example) |
Comment |
|---|---|---|
WLSFILE |
/masters/20231230/kpf_20231230_master_WLS_autocal-thar-all-eve_L1.fits |
Wavelength solution file used for this L1 file |
MONOTWLS |
1 |
Quality Control: 1 = L1 wavelength solution is monotonic |
SNRSC452 |
250.0 |
SNR of L1 SCI spectrum (SCI1+SCI2+SCI3; 95th %ile) near 452 nm (second bluest order); on Green CCD |
SNRSK452 |
250.0 |
SNR of L1 SKY spectrum (95th %ile) near 452 nm (second bluest order); on Green CCD |
SNRCL452 |
250.0 |
SNR of L1 CAL spectrum (95th %ile) near 452 nm (second bluest order); on Green CCD |
SNRSC548 |
250.0 |
SNR of L1 SCI spectrum (SCI1+SCI2+SCI3; 95th %ile) near 548 nm; on Green CCD |
SNRSK548 |
250.0 |
SNR of L1 SKY spectrum (95th %ile) near 548 nm; on Green CCD |
SNRCL548 |
250.0 |
SNR of L1 CAL spectrum (95th %ile) near 548 nm; on Green CCD |
SNRSC652 |
250.0 |
SNR of L1 SCI spectrum (SCI1+SCI2+SCI3; 95th %ile) near 652 nm; on Red CCD |
SNRSK652 |
250.0 |
SNR of L1 SKY spectrum (95th %ile) near 652 nm; on Red CCD |
SNRCL652 |
250.0 |
SNR of L1 CAL spectrum (95th %ile) near 652 nm; on Red CCD |
SNRSC747 |
250.0 |
SNR of L1 SCI spectrum (SCI1+SCI2+SCI3; 95th %ile) near 747 nm; on Red CCD |
SNRSK747 |
250.0 |
SNR of L1 SKY spectrum (95th %ile) near 747 nm; on Red CCD |
SNRCL747 |
250.0 |
SNR of L1 CAL spectrum (95th %ile) near 747 nm; on Red CCD |
SNRSC852 |
250.0 |
SNR of L1 SCI (SCI1+SCI2+SCI3; 95th %ile) near 852 nm (second reddest order); on Red CCD |
SNRSK852 |
250.0 |
SNR of L1 SKY spectrum (95th %ile) near 852 nm (second reddest order); on Red CCD |
SNRCL852 |
250.0 |
SNR of L1 CAL spectrum (95th %ile) near 852 nm (second reddest order); on Red CCD |
FR452652 |
1.2345 |
Peak flux ratio between orders (452nm/652nm) using SCI2 |
FR548652 |
1.2345 |
Peak flux ratio between orders (548nm/652nm) using SCI2 |
FR747652 |
1.2345 |
Peak flux ratio between orders (747nm/652nm) using SCI2 |
FR852652 |
1.2345 |
Peak flux ratio between orders (852nm/652nm) using SCI2 |
FR12M452 |
0.9000 |
median(SCI1/SCI2) flux ratio near 452 nm; on Green CCD |
FR12U452 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 452 nm; on Green CCD |
FR32M452 |
0.9000 |
median(SCI3/SCI2) flux ratio near 452 nm; on Green CCD |
FR32U452 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 452 nm; on Green CCD |
FRS2M452 |
0.9000 |
median(SKY/SCI2) flux ratio near 452 nm; on Green CCD |
FRS2U452 |
0.0010 |
uncertainty on the median(SKY/SCI2) flux ratio near 452 nm; on Green CCD |
FRC2M452 |
0.9000 |
median(CAL/SCI2) flux ratio near 452 nm; on Green CCD |
FRC2U452 |
0.0010 |
uncertainty on the median(CAL/SCI2) flux ratio near 452 nm; on Green CCD |
FR12M548 |
0.9000 |
median(SCI1/SCI2) flux ratio near 548 nm; on Green CCD |
FR12U548 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 548 nm; on Green CCD |
FR32M548 |
0.9000 |
median(SCI3/SCI2) flux ratio near 548 nm; on Green CCD |
FR32U548 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 548 nm; on Green CCD |
FRS2M548 |
0.9000 |
median(SKY/SCI2) flux ratio near 548 nm; on Green CCD |
FRS2U548 |
0.0010 |
uncertainty on the median(SKY/SCI2) flux ratio near 548 nm; on Green CCD |
FRC2M548 |
0.9000 |
median(CAL/SCI2) flux ratio near 548 nm; on Green CCD |
FRC2U548 |
0.0010 |
uncertainty on the median(CAL/SCI2) flux ratio near 548 nm; on Green CCD |
FR12M652 |
0.9000 |
median(SCI1/SCI2) flux ratio near 652 nm; on Red CCD |
FR12U652 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 652 nm; on Red CCD |
FR32M652 |
0.9000 |
median(SCI3/SCI2) flux ratio near 652 nm; on Red CCD |
FR32U652 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 652 nm; on Red CCD |
FRS2M652 |
0.9000 |
median(SKY/SCI2) flux ratio near 652 nm; on Red CCD |
FRS2U652 |
0.0010 |
uncertainty on the median(SKY/SCI2) flux ratio near 652 nm; on Red CCD |
FRC2M652 |
0.9000 |
median(CAL/SCI2) flux ratio near 652 nm; on Red CCD |
FRC2U652 |
0.0010 |
uncertainty on the median(CAL/SCI2) flux ratio near 652 nm; on Red CCD |
FR12M747 |
0.9000 |
median(SCI1/SCI2) flux ratio near 747 nm; on Red CCD |
FR12U747 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 747 nm; on Red CCD |
FR32M747 |
0.9000 |
median(SCI3/SCI2) flux ratio near 747 nm; on Red CCD |
FR32U747 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 747 nm; on Red CCD |
FRS2M747 |
0.9000 |
median(SKY/SCI2) flux ratio near 747 nm; on Red CCD |
FRS2U747 |
0.0010 |
uncertainty on the median(SKY/SCI2) flux ratio near 747 nm; on Red CCD |
FRC2M747 |
0.9000 |
median(CAL/SCI2) flux ratio near 747 nm; on Red CCD |
FRC2U747 |
0.0010 |
uncertainty on the median(CAL/SCI2) flux ratio near 747 nm; on Red CCD |
FR12M852 |
0.9000 |
median(SCI1/SCI2) flux ratio near 852 nm; on Red CCD |
FR12U852 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 852 nm; on Red CCD |
FR32M852 |
0.9000 |
median(SCI3/SCI2) flux ratio near 852 nm; on Red CCD |
FR32U852 |
0.0010 |
uncertainty on the median(SCI1/SCI2) flux ratio near 852 nm; on Red CCD |
FRS2M852 |
0.9000 |
median(SKY/SCI2) flux ratio near 852 nm; on Red CCD |
FRS2U852 |
0.0010 |
uncertainty on the median(SKY/SCI2) flux ratio near 852 nm; on Red CCD |
FRC2M852 |
0.9000 |
median(CAL/SCI2) flux ratio near 852 nm; on Red CCD |
FRC2U852 |
0.0010 |
uncertainty on the median(CAL/SCI2) flux ratio near 852 nm; on Red CCD |
The keywords above related to the signal-to-noise ratio in L1 spectra all start with ‘SNR’. These measurements were made using modules/quicklook/src/analyze_l1.py. The image below (click to enlarge) shows the spectral orders and wavelengths at which SNR is measured.
Keywords related to flux ratios between orders (FR452652, FR548652, FR747652, FR852652) are the ratios between the 95th percentile in flux for the spectral orders containing 452 nm, 548 nm, 747 nm, and 852 nm, all normalized by the spectral order containing 652 nm. These are the same spectral orders used for the SNR calculations and use the SCI2 orderlet.
Keywords related to orderlet flux ratios (e.g., FR12M452 and its uncertainty FR12U452) are computed in 500-pixel regions in the centers in the same spectral orders as are used for the SNR calculations.
L2 Primary Extension Header
The L2 file inherits all Level 0, 2D, and Level 1 keywords. Below are additional important keywords.
Keyword |
Value (example) |
Comment |
|---|---|---|
TIMCHKL2 |
1 |
Quality Control: 1 = consistent times in L2 file |
Radial Velocities
L2 RV Extension Header
The header to the RV extension (not the primary extension) contains this information about RVs computed using the CCF technique. CCD1 refers to the Green CCD (445-600 nm) and CCD2 refers to the Red CCD (600-870 nm).
To-do, add notes on:
recommendations for which RVs to use in papers
how the orders are averaged using weights.
precisely how the RVs are computed (refer to a paper on the CCF algorithm that we’re using)
how the errors are computed
is BJD = BJD TBD?
Test equation for rst syntax:
Keyword |
Value (example) |
Comment |
|---|---|---|
CCFRV |
19.4247572623 |
Average of CCD1RV and CCD2RV using weights from RV table |
CCFERV |
0.001175044 |
Error on CCFRV |
CCFRVC |
19.4247572623 |
Average of CCD1RVC and CCD2RVC using weights from RV table |
CCFERVC |
0.001175044 |
Error on CCFRVC |
CCD1ROW |
0 |
Row number in the RV table (below) of the bluest order on the Green CCD |
CCD1RV1 |
19.4247572623 |
RV (km/s) of SCI1 (all orders, Green CCD); corrected for barycentric RV |
CCD1ERV1 |
0.0013815112 |
Error on CCD1RV1 |
CCD1RV2 |
19.3879442221 |
RV (km/s) of SCI2 (all orders, Green CCD); corrected for barycentric RV |
CCD1ERV2 |
0.001175044 |
Error on CCD1RV2 |
CCD1RV3 |
19.3740241724 |
RV (km/s) of SCI3 (all orders, Green CCD); corrected for barycentric RV |
CCD1ERV3 |
0.0012185926 |
Error on CCD1RV3 |
CCD1RVC |
0.0 |
RV (km/s) of CAL (all orders, Green CCD); corrected for barycentric RV |
CCD1ERV |
0.0 |
Error on CCD1RVC |
CCD1RVS |
18.2490292404 |
RV (km/s) of SKY (all orders, Green CCD); corrected for barycentric RV |
CCD1ERVS |
0.0 |
Error on CCD1RVS |
CCD1RV |
19.395608349 |
RV (km/s) of average of SCI1/SCI2/SCI3 (all orders, Green CCD); corrected for barycentric RV |
CCD1ERV |
0.0007214256 |
Error on CCD1RV |
CCD1BJD |
2460237.787166463 |
Photon-weighted mid-time (BJD) for CCD1RV |
CCD2ROW |
35 |
Row number in the RV table (below) of the bluest order on the Red CCD |
CCD2RV1 |
19.4423673077 |
RV (km/s) of SCI1 (all orders, Red CCD); corrected for barycentric RV |
CCD2ERV1 |
0.004087698 |
Error on CCD2RV1 |
CCD2RV2 |
19.3979186805 |
RV (km/s) of SCI2 (all orders, Red CCD); corrected for barycentric RV |
CCD2ERV2 |
0.0034324475 |
Error on CCD2RV2 |
CCD2RV3 |
19.3808011301 |
RV (km/s) of SCI3 (all orders, Red CCD); corrected for barycentric RV |
CCD2ERV3 |
0.0035412025 |
Error on CCD2RV3 |
CCD2RVC |
0.0 |
RV (km/s) of CAL (all orders, Red CCD); corrected for barycentric RV |
CCD2ERVC |
0.0 |
Error on CCD2RVC |
CCD2RVS |
51.9730319697 |
RV (km/s) of SKY (all orders, Red CCD); corrected for barycentric RV |
CCD2ERVS |
0.0 |
Error on CCD2RVS |
CCD2RV |
19.4069470745 |
RV (km/s) of average of SCI1/SCI2/SCI3 (all orders, Red CCD); corrected for barycentric RV |
CCD2ERV |
0.0021111409 |
Error on CCD2RV |
CCD2BJD |
2460237.787150946 |
Photon-weighted mid-time (BJD) for CCD2RV |
L2 RV Extension
The RV extension in an L2 file contains the order-by-order RV information for each orderlet (SCI1, SCI2, SCI3, CAL, SKY) determined by the CCF technique. This extension is a FITS table that is converted into a Pandas dataframe if the L2 file is read by kpfpipe.models.level2.KPF2.from_fits(). The table rows correspond to the spectral orders, with the values of the keywords CCD1ROW and CCD2ROW in the RV extension header giving the rows where the Green and Red orders start, respectively. The table columns are listed below.
Column |
Value (example) |
Comment |
|---|---|---|
orderlet1 |
19.250267 |
RV (km/s) of SCI1 (Green CCD); corrected for barycentric RV |
orderlet2 |
19.264743 |
RV (km/s) of SCI2 (Green CCD); corrected for barycentric RV |
orderlet3 |
19.388630 |
RV (km/s) of SCI3 (Green CCD); corrected for barycentric RV |
s_wavelength |
4505.907677 |
starting wavelength for order |
e_wavelength |
4462.664498 |
ending wavelength for order |
segment no. |
0 |
Segment number (for full-order CCF RVs, segment no. = order no.) |
order no. |
0 |
Order number |
RV |
19.306370 |
RV (km/s) of average of SCI1/SCI2/SCI3 (Green CCD); corrected for barycentric RV |
RV error |
0.019248 |
error on ‘RV’ |
CAL RV |
0.0 |
RV (km/s) of CAL (Green CCD); corrected for barycentric RV |
CAL error |
0.0 |
error on ‘CAL RV’ |
SKY RV |
0.0 |
RV (km/s) of sKY (Green CCD); corrected for barycentric RV |
SKY error |
0.0 |
error on ‘SKY RV’ |
CCFBJD |
2.460238e+06 |
Photon-weighted mid-time (BJD) for CCD1RV |
Bary_RVC |
-8.729925 |
Barycentric RV (km/s) |
source1 |
GREEN_SCI_FLUX1 |
name of array for orderlet1 (SCI1) |
source2 |
GREEN_SCI_FLUX2 |
name of array for orderlet2 (SCI2) |
source3 |
GREEN_SCI_FLUX3 |
name of array for orderlet3 (SCI3) |
source CAL |
GREEN_CAL_FLUX |
name of array for CAL |
source SKY |
GREEN_SKY_FLUX |
name of array for SKY |
CCF Weights |
0.2590 |
weight for this order |
WLS Dictionaries
See Format of Wavelength Solution Dictionaries for details.
Notes on Dates and Times in KPF Files
To do: add notes here about how DATE-BEG, DATE-MID, and DATE-END are computed. There are other datetimes in the header that should be clarified. Also, explain how exposure midpoints are computed (using the exposure meter and DATE-BEG??), which leads to BJD and ultimately the barycentric corrections.