ACS Anneal Dates

Anneal Dates

ACS Annealing

This page contains a listing of all past and future anneal dates for the ACS/WFC detector. As part of the CCD Hot Pixel Annealing calibration program, the ACS detector is periodically annealed in an attempt to slow the growth of hot pixels that arise from radiation damage. For each anneal, the thermoelectric coolers are shutdown and the heaters are powered on to warm the detector up to about 19ºC over the span of ~12 hours. Before and after each anneal, four 1040 second darks frames and 4 bias frames are taken for monitoring purposes to determine the efficiacy of the annealing process as the detector continues to degrade from radiation damage. 

  • Upcoming Anneal Windows for Cycle 31

    Apr 22, 2024 - Apr 28, 2024
    May 20, 2024 - May 26, 2024
    Jun 17, 2024 - Jun 23, 2024
    Jul 15, 2024 - Jul 22, 2024
    Aug 12, 2024 - Aug 18, 2024
    Sep 9, 2024 - Sep 15, 2024
    Oct 7, 2024 - Oct 13, 2024

Completed Anneals

Completed Anneals 

Note, this list of completed anneals only contains anneals occuring after Servicing Mission 4 (SM4) which occurred in May of 2009.

Completed anneals by year

*The anneal originaly scheduled for June 23, 2021 was missed due to the HST safing on June 13, 2021.

Last Updated: 04/02/2024

Pre-footer

HST Help Desk 

Please contact the HST Help Desk with any questions.