The result of an observation with KPF (calibration or stellar) will be a single Flexible Image Transport System (FITS) file. This approach simplifies later analysis, and is preferred over the alternative scheme of separate FITS files for each detector or subsystem. The expected composition of a KPF FITS File is shown in the following table. For some observations, certain data is not needed, required, or available (for example, tip/tilt data is not required for a calibration exposure). Ideally in such cases the relevant extension will still be present (but perhaps empty, or ‘zeroed’). Such an approach will simplify later analysis, as all FITS files generated by KPF will have the same format. We envision two FITS files per observation, an "Exposure FITS file", and a "Processed FITS file". The exposure FITS file contains the spectra and the state of the observatory and subsystems, and is saved at the conclusion of the observation. The processed FITS file is the result of post-observation processing and analysis of the exposure FITS file, and contains additional information, such as the wavelength solution, computed RVs, etc. This distinction allows for future, refined calibrations and the creation of new processed FITS files, while leaving the exposure FITS files untouched.
| Data Unit Type | Description |
|---|---|
| Header | Observing time and date, instrument telemetry, etc. |
| Extension | Green Channel CCD Image (raw 2D spectrum) |
| Extension | Red Channel CCD Image (raw 2D spectrum) |
| Extension | Ca H&K Channel CCD Image (raw 2D spectrum) |
| Extension | Exposure Meter data |
| Extension | Tip/tilt mirror data |
KPF data products will contain as FITS keywords all telemetry and pipeline configuration parameters necessary to automatically run the Data Reduction Pipeline and separate diagnostic tests, and be in compliance with KOA and WMKP DRWG requirements. The different keywords added cumulatively to Level 0, 1, and 2 data are listed in the KPF DRP website (link TBD). These include observation location, observation type, file definition, calibration association, program identification, world coordinate system, spectrograph configuration, exposure meter configuration and other keywords. Keywords will be bundled with prefixes relevant to each subsystem or use.
Potential general header fields include date, time, and observatory location. Observatory state and telemetry (telescope, dome position, observatory temperature sensors, etc.) will also be included.
Potential header fields for devices and sensors throughout the system are shown here, grouped by subassembly.
| Device/Parameter | Type | Example |
|---|---|---|
| AO Bench enclosure hatch | Status | Open/closed |
| FIU enclosure hatch | Status | Open/closed |
| AO Bench Pickoff Mirror Stage | Position | Acquire/observe |
| FIU Calibration Stage | Status | In/out |
| ADC Stage 1 | Position | X degrees |
| ADC Stage 2 | Position | Y degrees |
| TT Mirror | Status | Reported values |
| FIU Temperature | Sensor Reading |
| Device/Parameter | Type | Example |
|---|---|---|
| Source in beam | Type | Th-Ar (daily), Th-Ar (gold), Broadband, etc. |
| Th-Ar (daily) power | Status | On/off |
| Th-Ar (gold) power | Status | On/off |
| Broadband power | Status | On/off |
| ND Filter in beam | Filter type | |
| Science Calibration Fiber Shutter | Status | Open/closed |
| Sky Calibration Fiber Shutter | Status | Open/closed |
| Simultaneous Calibration Fiber Shutter | Status | Open/closed |
| Lamp intensity monitory | Sensor Reading | |
| Calibration Unit emperature [C] | Sensor Reading |
| Device/Parameter | Type | Example |
|---|---|---|
| Atmospheric Pressure [m bar] | Sensor Reading | 600 |
| Relative Humidity [%] | Sensor Value | 40 |
| Vacuum Chamber Pressure, Start of Exposure [m bar] | Sensor Reading | |
| Vacuum Chamber Pressure, End of Exposure [m bar] | Sensor Reading | |
| Spectrometer temperature sensors | Sensor Reading | Eight sensors planned |
| Spectrometer Shutter | Status | Open/closed |
| Vacuum Valve | Status | Open/closed |
| Roughing Vacuum Pump | Status | On/off |
| Main Turbo Vacuum Pump | Status | On/off |
| Trimmer Vacuum Pump | Status | On/off |
| Device/Parameter | Type | Example |
|---|---|---|
| Green CCD parameters | Number | Readout rate, etc. |
| Exposure start time | Time | |
| Exposure start time | Time | |
| Green CCD temperature 1 [C] | Sensor Reading | |
| Green CCD temperature 2 [C] | Sensor Reading | |
| Green CCD package temperature 1 [C] | Sensor Reading | |
| Green CCD package temperature 2 [C] | Sensor Reading |
| Device/Parameter | Type | Example |
|---|---|---|
| Red CCD parameters | Number | Readout rate, etc. |
| Exposure start time | Time | |
| Exposure start time | Time | |
| Red CCD temperature 1 [C] | Sensor Reading | |
| Red CCD temperature 2 [C] | Sensor Reading | |
| Red CCD package temperature 1 [C] | Sensor Reading | |
| Red CCD package temperature 2 [C] | Sensor Reading |
| Device/Parameter | Type | Example |
|---|---|---|
| Track 1 start counts | Counter Reading | 123456 |
| Track 1 end counts | Counter Reading | 123516 |
| Track 1 counts during exposure | Counter Reading | 60 |
| Track 2 start counts | Counter Reading | 1234 |
| Track 2 end counts | Counter Reading | 1264 |
| Track 2 counts during exposure | Counter Reading | 30 |
| Verification Flag | Status | OK/Error |
| Device/Parameter | Type | Example |
|---|---|---|
| Exposure Meter CCD parameters | Number | Readout rate, etc. |
| Exposure start time | Time | |
| Exposure start time | Time | |
| Exposure Meter CCD temperature [C] | Sensor Reading |
| Device/Parameter | Type | Example |
|---|---|---|
| Ca HK Shutter | Status | Open/closed |
| Exposure start time | Time | |
| Exposure start time | Time | |
| Ca HK CCD parameters | Number | Readout rate, etc. |
| Ca HK CCD temperature [C] | Sensor Reading |
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