E.17 The Cycle 30 Calibration Plan

The Cycle 30 calibration plan was executed from November 2022 through October 2023. The individual programs are listed in Table E.18 and are described in more detail on the WFC3 Calibration Plan webpage. Following the link to Cycle 30 Calibration, a similar table may be found with 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 30 section also links to a PDF presentation summarizing WFC3 usage and comparing the Cycle 30 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 30 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

Four new calibration programs will supplement the standard monitoring. These programs (17261, 17262, 17265, 17271) were designed to:

• Track any changes in the IR sensitivity using repeated scan mode observations of M35
• Measure the non-repeatability of the mechanical shutter using repeated short exposures of a bright spectrophotometric standard with the UVIS grism
• Provide users with faint-source CTE-loss curves for backgrounds between 30 e- and 100 e-
• Investigate the UVIS EE and PSF spatial structure at radii greater than 150 pixels using saturated exposures of a white dwarf standard

The results of these calibration programs will be documented in Instrument Science Reports on the WFC3 website at:
http://www.stsci.edu/hst/instrumentation/wfc3/documentation/instrument-science-reports-isrs

Table E.18: The Cycle 30 Calibration Programs