E.18 The Cycle 31 Calibration Plan

The Cycle 31 calibration plan is being executed from November 2023 through October 2024. The individual programs are listed in Table E.19 and are described in more detail on the WFC3 Calibration Plan webpage. In the Cycle 31 Calibration section, a similar table contains direct links to the Phase II programs and observation dates. This information may alternately be accessed via the HST Program Information webpage by entering the Proposal ID.

The WFC3 Cycle 31 section also links to a PDF presentation summarizing WFC3 usage in the latest cycle and comparing the current plan with the prior cycle. This document contains more details on the calibration justification and in many cases includes supporting figures with the latest results from regular monitoring.

The Cycle 31 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

One new calibration program will supplement the standard monitoring, and is designed to:

  • Track changes in the IR sensitivity using repeated scan mode observations of M35.

The results of these calibration programs will be documented in Instrument Science Reports on the WFC3 website at:

Table E.19: The Cycle 31 Calibration Programs

17345WFC3 UVIS Anneal
17346WFC3 UVIS Bowtie Monitor
17347WFC3 UVIS CCD Daily Monitor Part 1
17348WFC3 UVIS CCD Daily Monitor Part 2
17349WFC3 UVIS CCD Daily Monitor Part 3
17350WFC3 UVIS CCD Unflashed (CTE) Monitor
17351WFC3 UVIS Post-flash Monitor
17352WFC3 UVIS CCD Gain Stability
17353WFC3 UVIS CTI Monitor (EPER)
17354WFC3 UVIS CTE Monitor (star cluster)
17355WFC3 Characterization of UVIS traps with Charge Injection
17356WFC3 UVIS CTE Internal Monitor
17357WFC3 IR Dark Monitor
17358WFC3 IR Linearity Monitor
17359WFC3 IR Gain Monitor
17360WFC3 UVIS Shutter Monitoring
17361WFC3 UVIS and IR Photometry
17362WFC3 Time Dependent Sensitivity
17363WFC3 IR Time Dependent Sensitivity in Clusters
17364HST Focus and Optical Montior
17365WFC3 UVIS Grism Wavelength Calibration
17366WFC3 IR Grism Wavelength Calibration
17367WFC3 IR Flux/Trace Monitor
17368WFC3 UVIS Pixel-to-Pixel QE Variations via Internal Flats
17369WFC3 UVIS Internal Flats
17370WFC3 IR Internal Flats
17371WFC3 CSM Monitor with Earth Flats
17372WFC3 Astrometric Scale Monitoring

WFC3 IR Time-Dependent Sensitivity: Spatial Scans