Overview

WFC3 Calibration Plans

Initial calibration of WFC3 has taken place on the ground in simulated orbital conditions. Shortly after launch, observations will be used to assess the on-orbit performance of the camera during a period called SMOV. As with the other HST instruments, calibrations will be periodically updated through new observations campaigns every year. The results of these calibration programs will be documented as they become available via Instrument Science Reports on the WFC3 ISR webpage.

A summary of HST calibration in the current cycle, and a comparison with prior cycles, may be found on the HST Calibration Plan webpage. Statistics on WFC3 usage for science programs may be found on the Instrument Usage webpage.

 

 

Cycle 28 Calibration

11/2020-10/2021 (12 months)

In Cycle 28 the WFC3 team will carry out an extended calibration program to monitor the behavior of the UVIS and IR channels and to provide the best calibration data for scientific programs.

The Cycle 28 calibration plan was designed to:

  • Maintain and update the standard reference files (biases, darks, linearity, CTE traps, UVIS anomalous QE pixels, post-flash)
  • Monitor the health of the instrument (throughput, gain, hysteresis, bad/hot pixels, sink pixels, CTE decline, stability of the post-flash LED, filter transmission, state of the CSM, number of IR blobs, wavelength and flux stability of the grisms)
  • Support new initiatives and obtain supplemental (non-routine) calibration data

In this cycle, the IR Grism Flux Monitor (program 16408) has been modified to:

  • Quantify sensitivity losses in the IR grisms by supplementing the annual GD153 data with two additional WD standards

Three new calibration programs will supplement the standard monitoring. These programs (16039, 16040, 16041) were designed to:

  • Check whether the IR filters are losing sensitivity, or if losses are limited to the IR grisms

  • Recheck the optimal background (post-flash) level, as CTE losses continue to grow

  • Measure the impact of CTE on very faint stars

Cycle 28 Calibration Program Slides

Cycle 27 Calibration

11/2019 - 10/2020 (12 months)

 

In Cycle 27 the WFC3 team will carry out an extended calibration program to monitor the behavior of the UVIS and IR channels and to provide the best calibration data for scientific programs.

 

The Cycle 27 calibration plan was designed to:

• Maintain and update the standard reference files (biases, darks, linearity, CTE traps, UVIS anomalous QE pixels, post-flash)

• Monitor the health of the instrument (throughput, gain, hysteresis, bad/hot pixels, sink pixels, CTE decline, stability of the post-flash LED, filter transmission, state of the CSM, number of IR blobs, wavelength and flux stability of the grisms)

• Support new initiatives and obtain supplemental (non-routine) calibration data

 

In this cycle, two standard monitoring programs have been restructured from Cycle 26. These programs (16021, 16030) were designed to:

• Quantify losses in the UVIS sensitivity using spatial scans (previously called ‘UVIS Contamination Monitor)  

• Monitor the ‘UVIS and IR Photometric Calibration’ via staring mode observations of HST standards

 

Five new calibration programs will supplement the standard monitoring. These programs (16020, 16022, 16023, 16029, 16031) were designed to:

• Measure the stability of the tungsten lamp output immediately after turn-on

• Refine the UVIS grism wavelength calibration across the entire detector with better 2D sampling

• Finalize the flux calibration of the UVIS grism with similar spatial sampling as for the wavelength calibration

• Recheck the optimal UVIS background level to mitigate CTE losses 

• Check for time dependent sensitivity in the IR detector grisms and filters

Cycle 27 Calibration Program Slides

Cycle 26 Calibration

11/2018 - 10/2019 (12 months)

In Cycle 26 the WFC3 team will carry out an extended calibration program to monitor the behavior of the UVIS and IR channels and to provide the best calibration data for scientific programs.

Cycle 26 calibration plan was designed to:

  • Maintain and update the standard reference files (biases, darks, linearity, CTE traps, UVIS anomalous QE pixels, post-flash)
  • Monitor the health of the instrument (throughput, gain, hysteresis, bad/hot pixels, sink pixels, CTE decline, stability of the post-flash LED, filter transmission, state of the CSM, number of IR blobs, wavelength and flux stability of the grisms)
  • Support new initiatives and obtain supplemental (non-routine) calibration data

In this cycle, two new calibration programs will supplement the standard monitoring data. These programs were designed to:

  • Cross-calibrate the HST focus values derived from the OTA Focus monitor (based on UVIS/F410M observations) with the focus values derived empirically from the WFC3/UVIS PSF database, which has many more F606W observations
  • Characterize the decay of IR persistence at short time-scales (t <300 sec), where the observed residual signal deviates from the current power-law model

Cycle 26 Calibration Program Slides

Cycle 25 Calibration

11/2017 - 10/2018 (12 months)

In Cycle 25 the WFC3 team will carry out an extended calibration program to monitor the behavior of the UVIS and IR channels and to provide the best calibration data for scientific programs. 

Cycle 25 calibration plan was designed to:

  • maintain and update the standard reference files (biases, darks, linearity, CTE traps, UVIS anomalous QE pixels, post-flash)
  • monitor the health of the instrument (throughput, gain, hysteresis, bad/hot pixels, sink pixels, CTE decline, stability of the post-flash LED, filter transmission, state of the CSM, number of IR blobs, wavelength and flux stability of grisms)
  • improve the precision of the UVIS contamination monitor using scanned observations of of photometric standards
  • quantify color terms for the UVIS filters and recheck the photometric calibration at the center of the detector
  • test a strategy to mitigate IR persistence using the calibration lamps to fill charge traps prior to obtaining science observations

Cycle 25 Calibration Program Slides

Cycle 24 Calibration

11/2016 - 10/2017 (12 months)

During Cycle 24 the WFC3 team will carry on an extended calibration program designed to measure and monitor the behavior of both the UVIS and IR channels of WFC3 and to provide the best calibration data for the approved scientific programs. 

Cycle 24 calibration plan was designed to:

  • maintain and update the standard reference files (biases, darks, linearity, CTE traps, UVIS anomalous QE pixels, post-flash)
  • monitor the health of the instrument (throughput, gain, hysteresis, bad/hot pixels, sink pixels, CTE decline, stability of the post-flash LED, filter transmission, state of the CSM, number of IR blobs, wavelength and flux stability of grisms)
  • test the precision of the IR count rate non-linearity correction for faint targets and determine whether a wavelength-dependent correction is required
  • improve the precision of the UVIS contamination monitor by making use of spatially scanned observations of photometric standards
  • re-evaluate the 2013 UVIS pixel-based CTE model and verify that the recommended post-flash level has not changed

Cycle 24 Calibration Program Slides

Cycle 23 Calibration

11/2015 - 10/2016 (12 months)

During Cycle 23 the WFC3 team will carry on an extended calibration program designed to measure and monitor the behavior of both the UVIS and IR channels of WFC3 and to provide the best calibration data for the approved scientific programs.

Cycle 23 Calibration Program Slides

Cycle 22 Calibration

11/2014 - 10/2015 (12 months)

During Cycle 22 the WFC3 team will carry on an extended calibration program designed to measure and monitor the behavior of both the UVIS and IR channels of WFC3 and to provide the best calibration data for the approved scientific programs.

Cycle 22 Calibration Program Slides

Cycle 21 Calibration

11/2013 - 10/2014 (12 months)

During Cycle 21 the WFC3 team will carry on an extended calibration program designed to measure and monitor the behavior of both the UVIS and IR channels of WFC3 and to provide the best calibration data for the approved scientific programs.

Cycle 21 Calibration Program Slides

Cycle 20 Calibration

11/05/2012 - 11/04/2013 (12 months)

During Cycle 20 the WFC3 team will carry on an extended calibration program designed to measure and monitor the behavior of both the UVIS and IR channels of WFC3 and to provide the best calibration data for the approved scientific programs.

Cycle 20 Calibration Program Slides

Cycle 19 Calibration

10/01/2011 - 09/30/2012 (12 months)

During Cycle 19 the WFC3 team will carry on an extended calibration program designed to measure and monitor the behavior of both the UVIS and IR channels of WFC3 and to provide the best calibration data for the approved scientific programs.

Cycle 19 Calibration Program Slides

Cycle 18 Calibration

Cycle 18 Calibration Program

Cycle 17 Calibration

Cycle 17 Calibration Program

SMOV Plans

Servicing Mission Orbital Verification (SMOV) will take place shortly after the installation of WFC3 on HST during Servicing Mission 4. Below is a list of the planned tests to be executed to verify the performance of the instrument.

Ground Testing

WFC3 has undergone several iterations of fully integrated instrument testing. This testing took place at Goddard Space Flight Center (GSFC). During thermal vacuum (TV) testing, reference file data are collected and the instrument is characterized and calibrated. The first two TV sessions took place in the winter of 2004 and spring of 2007. TV3 testing is scheduled for early spring of 2008. The links below connect to pages giving the results from the various TV campaigns.

(Up to date calibration information is located in Howard Bushouse's Calibration Plan webpage. This page contains links to the science calibration test plan, SMS spreadsheets, and other associated documentation.)

Link to
TV1 Results
Link to
TV2 Results
Link to
TV3 Results

TV Supporting Documents

Side Switch Contingency Plan

WFC3 Side Switch Servicing Mission Orbital Verification (SS SMOV) is a contingency plan for a WFC3 re-commissioning on Side 1, following a side switch.

Detailed Descriptions of the SS SMOV Activities

LAST UPDATED: 11/10/2020

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