Interferometric Calibrations are mostly measured on internal source (to monitor only the instrument) or on astronomical calibrators (for the full system efficiency and to calibrate science data.
Most of the time, astronomical calibrators are observed before and after the science target to provide the best accurate calibrations.
The instrument efficiency is measured during the day on the internal lamp and as well during the night on the astronomical object when its flux is known.
Most of the calibrators uised by the tool have a known magnitude.
QC1_parameters
There are 2 different trending plots on the astronomical calibrators when their flux is known:
Instrument + UT+ sky transmission.
Scoring&thresholds Efficiency
The value of the thresholds have been defined together with the Instrument scientist.
History
The evolution of the transmission on the AT is shown here
Algorithm Efficiency
The pipeline calculates the visibilities on the 6 baselines, the 3 closure phases as well as the transmission of each beam when the photometry of the object observed is known.
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Visibility and Closure Phase on Astromical Calibrators
ESO provides to the observer a tool to retrieve the calibrator best suitable for their observations. This tool is available under
QC1_parameters
FITS key |
QC1 database: table, name |
definition |
class* |
HC_plot** |
more docu |
QC.PHI123.AVG | pionier_fringe..phi123_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
QC.PHI124.AVG | pionier_fringe..phi124_avg | average phase closure | CAL | | [docuSys coming] |
QC.PHI134.AVG | pionier_fringe..phi134_avg | average phase closure | CAL | | [docuSys coming] |
QC.PHI234.AVG | pionier_fringe..phi234_avg | average phase closure | CAL | | [docuSys coming] |
QC.SNR12.AVG | pionier_fringe..snr12_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
QC.SNR13.AVG | pionier_fringe..snr13_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
QC.SNR14.AVG | pionier_fringe..snr14_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
QC.SNR23.AVG | pionier_fringe..snr23_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
QC.SNR24.AVG | pionier_fringe..snr24_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
QC.SNR34.AVG | pionier_fringe..snr34_avg | average SNR per baseline SNR=SNRU/SNRL | CAL | | [docuSys coming] |
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter
**There might be more than one. |
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fringes (reconstructed as seen during the observation)
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Trending
When fringes are obtained on a target (Science or astronomical calibrator), its uncalibrated Visibility and closure phase is calculated by the pipeline.
The HC plots Visibility and Visibility (night) shows the Visibilities on the last 3 months of data and the ones measured during the observing night.
The closure phases are also trended here
Scoring&thresholds Visibility and Closure Phase on Astromical Calibrators
These data are not scored as they depend on a lot of "external" factors : baselines of observations, atmospheric conditions, tracking of the delay lines
History
The evolution of the Visibilities is shown here
Algorithm Visibility and Closure Phase on Astromical Calibrators
The pipeline uses the fringe data contained in the raw files to reduce them into uncalibrated measurements of the visibilities and the closure phases. It is done file by file (typically a PIONIER observation contains 5 files).
The pipeline averages the data over the 100 scans (standard exposure).
Transfer Function on Calibrators
ESO provides to the observer a tool to retrieve the calibrator best suitable for their observations. This tool is available under . This catalog includes diameters of more than 440000 objects.
QC1_parameters
FITS key |
QC1 database: table, name |
definition |
class* |
HC_plot** |
more docu |
QC.TFVIS12.AVG | pionier_fringe..tfvis12_avg | average TF per baseline | CAL | | [docuSys coming] |
QC.TFVIS13.AVG | pionier_fringe..tfvis13_avg | average TF per baseline | CAL | | [docuSys coming] |
QC.TFVIS14.AVG | pionier_fringe..tfvis14_avg | average TF per baseline | CAL | | [docuSys coming] |
QC.TFVIS23.AVG | pionier_fringe..tfvis23_avg | average TF per baseline | CAL | | [docuSys coming] |
QC.TFVIS24.AVG | pionier_fringe..tfvis24_avg | average TF per baseline | CAL | | [docuSys coming] |
QC.TFVIS34.AVG | pionier_fringe..tfvis34_avg | average TF per baseline | CAL | | [docuSys coming] |
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter
**There might be more than one. |
Trending
When fringes are obtained on an astronomical calibrator its uncalibrated Visibility and closure phase are calculated by the pipeline. If the calibrator has a known diameter (and associated error), the pipeline calculates its Transfer Function.
The HC plots Transfer Function and Transfer Function (night) shows the Transfer Function on the last 3 months of data and the ones measured during the observing night.
Scoring&thresholds Transfer Function on Calibrators
These data are not scored in the HC plots but are used to assess the quality of the night.
A calibrator should be an object as small as possible for the observing baselines, so its TF should be close to 1. The TF measured on the same object, on the same baselines and not too far in time (to have the same atmospheric conditions) should not show a high scatter,
History
The evolution of the TF is shown here
Algorithm Transfer Function on Calibrators
The pipeline uses the uncalibrated measurements of the visibilities and the closure phases calculated previously as well as the diametre of the calibrator (if found) to calculate the Transfer Function.
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