WFSC Overheads

JWST's Astronomer’s Proposal Tool (APT) estimates duration for each step in the proposal. This page provides an accounting of durations specific to WFSC (Wavefront Sensing and Control) visits.

Additions to visit overhead

The NIRCam end-of-visit script is called at the end of each WFSC visit, so the timings are consistent with NIRCam.

Filter/pupil wheel timing model

The model is consistent with NIRCam.

Exposure overheads

NIRCam and FGS (in the case of Global Alignment) values are used.

OSS compilation overhead

Unless noted otherwise, the WFSC OSS compilation time is 30 seconds per exposure specification, not including target acq exposures. The OSS compilation time for target acq is subsumed into the flat 600-second TA overhead.


WFSC NIRCam coarse phasing

Visit overheads include two subarray configuration times (one to configure the 96x96 subarray for the In-Focus exposures and one to configure back to full-frame for the rest of the exposures). Each of these is 50 seconds and the first is included in initial overheads.

Change log

Version 1 (June 6, 2017)

  1. Initial version.