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 WFC detector is periodically annealed to slow the growth of hot pixels that arise from radiation damage. For each anneal, the thermoelectric coolers are shut down and the heaters are powered on to warm the detector up to about 20ºC 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 efficiency of the annealing process as the detector continues to degrade from radiation damage.
Upcoming Anneal Windows for Cycle 33
Jun 1, 2026 - Jun 7, 2026Jun 29, 2026 - Jul 5, 2026Jul 27, 2026 - Aug 2, 2026Aug 24, 2026 - Aug 30, 2026Sep 21, 2026 - Sep 27, 2026Oct 19, 2026 - Oct 25, 2026
Completed Anneals
Completed Anneals
Note, this list of completed anneals only contains anneals occurring after Servicing Mission 4 (SM4) which occurred in May of 2009.
Completed anneals by year
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MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 61057.387 2026-01-17 09:17:33 Jan 17 17980 17977 61085.461 2026-02-14 11:03:47 Feb 14 17980 17977 61109.998 2026-03-10 23:57:38 Mar 10 17980 17977 61137.493 2026-04-07 11:49:54 Apr 07 17980 17977 61164.388 2026-05-04 09:18:34 May 04 17980 17978 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 60693.149 2025-01-18 03:34:40 Jan 18 17657 17653 60717.608 2025-02-11 14:35:56 Feb 11 17657 17653, 17654 60745.876 2025-03-11 21:01:28 Mar 11 17657 17654 60762** 2025-03-28 00:00:00 Mar 28 - - 60772.598 2025-04-07 14:20:27 Apr 07 17657 17654 60801.174 2025-05-06 04:10:00 May 06 17657 17654 60832.079 2025-06-06 01:54:08 Jun 06 17657 17654, 17655 60856.736 2025-06-30 17:40:24 Jun 30 17657 17655 60888.921 2025-08-01 22:06:27 Aug 01 17657 17655 60915.317 2025-08-28 07:36:06 Aug 28 17657 17655 60941.584 2025-09-23 14:00:32 Sep 23 17657 17655 60970.794 2025-10-22 19:04:09 Oct 22 17657 17655 60996.571 2025-11-17 13:42:58 Nov 17 17980 17655, 17977 61030.026 2025-12-21 00:37:14 Dec 21 17980 17977 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 60314.351 2024-01-05 08:25:16 Jan 05 17337 60339.416 2024-01-30 09:59:43 Jan 30 17337 17333 60366.348 2024-02-26 08:20:31 Feb 26 17337 17333, 17334 60394.907 2024-03-25 21:45:26 Mar 25 17337 17334 60445.512 2024-05-15 12:16:42 May 15 17337 17334 60475.949 2024-06-14 22:46:00 Jun 14 17337 17334 60499.835 2024-07-08 20:03:00 July 08 17337 17334, 17335 60526.032 2024-08-04 00:45:36 Aug 04 17337 17335 60553.804 2024-08-31 19:17:15 Aug 31 17337 17335 60576.694 2024-09-23 16:39:53 Sep 23 17337 17335 60609.802 2024-10-26 19:14:14 Oct 26 17337 17335 60633.937 2024-11-19 22:29:15 Nov 19 17657 17653 60663.490 2024-12-19 11:45:38 Dec 19 17657 17653 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 59951.644
2023-01-07 15:27:36 Jan 07 16974 59979.824
2023-02-04 19:46:55 Feb 04 16974 60005.188
2023-03-02 04:30:43 Mar 02 16974 60030.334
2023-03-27 08:01:36 Mar 27 16974 60062.530
2023-04-28 12:42:33 Apr 28 16974 60088.101 2023-05-24 02:25:06 May 24 16974 16971 60114.561 2023-06-19 13:28:21 Jun 19 16974 16971, 16972 60144.850 2023-07-19 20:23:23 Jul 19 16974 16972 60171.404 2023-08-15 09:42:26 Aug 15 16974 16972 60204.161 2023-09-17 03:51:57 Sep 17 16974 16972 60228.557 2023-10-11 13:21:22 Oct 11 16974 16972 60255.446 2023-11-07 10:41:54 Nov 07 17337 17333 60286.183 2023-12-08 04:23:04 Dec 08 17337 17333 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 59586.868
2022-01-07 20:49:55
Jan 07 16526 16522 59615.076
2022-02-05 01:49:55 Feb 05 16526 59638.989
2022-02-28 23:43:31 Feb 28 16526 59666.622
2022-03-28 14:55:38 Mar 28 16526 59697.070
2022-04-28 01:40:53 Apr 28 16526 59722.734
2022-05-23 17:37:04 May 23 16526 59751.351
2022-06-21 08:25:50 Jun 21 16526 59778.493
2022-07-18 11:49:55 Jul 18 16526 59808.046
2022-08-17 01:05:44 Aug 17 16526 59834.571
2022-09-12 13:42:35 Sep 12 16526 59866.947
2022-10-14 22:44:13 Oct 14 16526 59895.260
2022-11-12 06:14:11 Nov 12 16974 59923.495
2022-12-10 11:52:38 Dec 10 16974 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 59219.363 2021-01-05 08:42:22
Jan 05 16382 16377 59246.835 2021-02-01 20:02:58 Feb 01 16382 16377 59278.006 2021-03-05 00:09:05 Mar 03 16382 16378 59305.285 2021-04-01 06:50:47 Apr 01 16382 16378 59331.904 2021-04-27 21:41:35 Apr 27 16382 16378 59362.353 2021-05-28 08:28:11 May 28 16382 16378 - - Jun 23* - - 59412.211
2021-07-17 05:03:18 Jul 17 16382 16379 59448.023
2021-08-22 00:32:59 Aug 22 16382 59470.343
2021-09-13 08:14:36 Sep 13 16382 59498.396
2021-10-11 09:30:19 Oct 11 16382 59528.928
2021-11-10 22:16:36 Nov 10 16526 59555.377
2021-12-07 09:03:29 Dec 07 16526 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 58857.1042020-01-09 02:30:42Jan 0915762 15757 58882.611
2020-02-03 14:40:32Feb 0315762 15757 58912.8632020-03-04 20:42:07Mar 0415762 15758 58939.2202020-03-31 05:15:17Mar 3158967.1302020-04-28 03:07:32Apr 2858998.3632020-05-29 08:43:24May 2959026.4522020-06-26 10:50:22Jun 2659050.5332020-07-20 12:47:20Jul 2059080.575
2020-08-19 13:48:04
Aug 19 15762 15759 59111.257
2020-09-19 06:10:41
Sep 19 15762 15759 59136.138
2020-10-14 03:18:43
Oct 14 15762 15759 59163.636 2020-11-10 15:16:01
Nov 10 16382 16377 59191.155 2020-12-08 03:43:00 Dec 08 16382 16377 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 58485.588 2019-01-02 14:07:03 Jan 02 15524 15519 58514.564 2019-01-31 13:32:52 Jan 31 15524 15519 58542.812 2019-02-28 19:29:33 Feb 28 15524 15519 58576.165 2019-04-03 03:58:09 Apr 03 15524 15520 58606.255 2019-05-03 06:06:41 May 03 15524 15520 58634.765 2019-05-31 18:21:31 May 31 15524 15520 58660.463 2019-06-26 11:07:12 Jun 26 15524 15520 58687.139 2019-07-23 03:20:04 Jul 23 15524 15521 58715.7292019-08-20 17:29:27Aug 2058747.3552019-09-21 08:30:52Sep 2158773.2582019-10-17 06:11:37Oct 1758801.8012019-11-14 19:13:17Nov 1458827.9182019-12-10 22:01:36Dec 1015757 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 58130.01604 2018-01-12 00:23:06.000 Jan 12 14951 14946 58155.47966 2018-02-06 11:30:43.000 Feb 06 14951 14946, 14947 58184.84515 2018-03-07 20:17:01.000 Mar 07 14951 14947 58213.42322 2018-04-05 10:09:26.000 Apr 05 14951 14947 58241.72559 2018-05-03 17:24:51.000 May 03 14951 14947 58269.10294 2018-05-31 02:28:14.000 May 31 14951 14947 58295.55602 2018-06-26 13:20:40.000 Jun 26 14951 14947,14948 58323.52804 2018-07-24 12:40:23.000 Jul 24 14951 14948 58350.66745 2018-08-20 16:01:08.000 Aug 20 14951 14948 58381.8297 2018-09-20 19:54:46.000 Sep 20 14951 14948 58418.56235 2018-10-27 13:29:47.000 Oct 27 14951 14948 58458.54705 2018-12-06 13:07:45.000 Dec 06 15524 15519 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 57764.54578704 2017-01-11 13:05:56 Jan 11 14509 14506 57791.47663194 2017-02-07 11:26:21 Feb 07 14509 14506 57820.79722222 2017-03-08 19:08:00 Mar 08 14509 14506,14517 57846.48987269 2017-04-03 11:45:25 Apr 03 14509 14517 57878.31895833 2017-05-05 07:39:18 May 05 14509 14517 57904.05841435 2017-05-31 01:24:07 May 31 14509 14517 57930.653275465 2017-06-26 15:40:43 Jun 26 14509 14517,14518 57960.28715278 2017-07-26 06:53:30 Jul 26 14509 14518 57989.85730324 2017-08-24 20:34:31 Aug 24 14509 14518 58017.40094907 2017-09-21 09:37:22 Sep 21 14509 14518 58043.43321759 2017-10-17 10:23:50 Oct 17 14509 14518 58071.42313657 2017-11-14 10:09:19 Nov 14 14951 14946 58100.81184028 2017-12-13 19:29:03 Dec 13 14951 14946 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 57400.0650116 2016-01-13 01:33:37 Jan 13 14400 14395 57429.3407639 2016-02-11 08:10:42 Feb 11 14400 14395, 14396 57456.8539468 2016-03-09 20:29:41 Mar 09 14400 14396 57482.4529282 2016-04-04 10:52:13 Apr 04 14400 14396 57510.870162 2016-05-02 20:53:02 May 02 14400 14396 57543.4526505 2016-06-04 10:51:49 Jun 04 14400 14396 57570.19373843 2016-07-01 04:38:59 Jul 01 14400 14396, 14397 57594.92002315 2016-07-25 22:04:50 Jul 25 14400 14397 57624.06425926 2016-08-24 01:32:32 Aug 24 14400 14397 57656.09380787 2016-09-25 02:15:05 Sep 25 14400 14397 57680.63887731 2016-10-19 15:19:59 Oct 19 14400 14397 57709.13311343 2016-11-17 03:11:41 Nov 17 14509 14506 57734.57861111 2016-12-12 13:53:12 Dec 12 14509 14506 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 57037.8675 2015-01-15 20:49:12 Jan 15 13957 13952 57065.5853241 2015-02-12 14:02:52 Feb 12 13957 13952, 13953 57094.2354282 2015-03-13 05:39:01 Mar 13 13957 13953 57122.8975579 2015-04-10 21:32:29 Apr 10 13957 13953 57148.1100579 2015-05-06 02:38:29 May 06 13957 13953 57176.1690278 2015-06-03 04:03:24 Jun 03 13957 13953 57204.8670139 2015-07-01 20:48:30 Jul 01 13957 13954 57232.8155671 2015-07-29 19:34:25 Jul 29 13957 13954 57261.5466204 2015-08-27 13:07:08 Aug 27 13957 13954 57289.54009259 2015-09-24 12:57:44 Sep 24 13957 13954 57317.97979166 2015-10-22 23:30:54 Oct 22 13957 13954, 14395 57344.5475 2015-11-18 13:08:24 Nov 18 14400 14395 57372.3538657 2015-12-16 08:29:34 Dec 16 14400 14395 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 56674.3125347 2014-01-17 07:30:03 Jan 17 13594 13589,13590 56701.7188194 2014-02-13 17:15:06 Feb 13 13594 13590 56726.8593981 2014-03-10 20:37:32 Mar 10 13594 13590 56756.0949074 2014-04-09 02:16:40 Apr 09 13594 13590 56785.7103819 2014-05-08 17:02:57 May 08 13594 13590 56814.61375 2014-06-06 14:43:48 Jun 06 13594 13590,13591 56840.6892477 2014-07-02 16:32:31 Jul 02 13594 13591 56867.3453125 2014-07-29 08:17:15 Jul 29 13594 13591 56895.4138079 2014-08-26 09:55:53 Aug 26 13594 13591 56923.7255208 2014-09-23 17:24:45 Sep 23 13594 13591 56952.5708449 2014-10-22 13:42:01 Oct 22 13594 13591,13952 56980.5410417 2014-11-19 12:59:06 Nov 19 13957 13952 57007.3671875 2014-12-16 08:48:45 Dec 16 13957 13952 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 56309.7832986 2013-01-17 18:47:57 Jan 17 13157 13152 56337.0979282 2013-02-14 02:21:01 Feb 14 13157 13152,13153 56365.5201968 2013-03-14 12:29:05 Mar 14 13157 13153 56394.5465162 2013-04-12 13:06:59 Apr 12 13157 13153 56421.9709491 2013-05-09 23:18:10 May 09 13157 13153 56451.4565278 2013-06-08 10:57:24 Jun 08 13157 13153 56476.8008218 2013-07-03 19:13:11 Jul 03 13157 13154 56507.0831481 2013-08-03 01:59:44 Aug 03 13157 13154 56535.4341551 2013-08-31 10:25:11 Aug 31 13157 13154 56563.359537 2013-09-28 08:37:44 Sep 28 13157 13154 56587.7998611 2013-10-22 19:11:48 Oct 22 13157 13154,13589 56614.4816898 2013-11-18 11:33:38 Nov 18 13594 13589 56647.6459722 2013-12-21 15:30:12 Dec 21 13594 13589 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 55943.5233912 2012-01-17 12:33:41 Jan 17 12732 12729 55976.1220602 2012-02-19 02:55:46 Feb 19 12732 12729,12782 56000.3352778 2012-03-14 08:02:48 Mar 14 12732 12782 56028.6262731 2012-04-11 15:01:50 Apr 11 12732 12782 56057.09 2012-05-10 02:09:36 May 10 12732 12782 56086.5439583 2012-06-08 13:03:18 Jun 08 12732 12782 56111.0854167 2012-07-03 02:03:00 Jul 03 12732 12782,12783 56140.4594213 2012-08-01 11:01:34 Aug 01 12732 12783 56171.3891435 2012-09-01 09:20:22 Sep 01 12732 12783 56195.2391088 2012-09-25 05:44:19 Sep 25 12732 12783 56228.2963079 2012-10-28 07:06:41 Oct 28 12732 12783,13152 56253.0775347 2012-11-22 01:51:39 Nov 22 13157 13152 56283.2698264 2012-12-22 06:28:33 Dec 22 13157 13152 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 55580.2098264 2011-01-19 05:02:09 Jan 19 12387 12384 55607.7286574 2011-02-15 17:29:16 Feb 15 12387 12384, 12397 55637.4116898 2011-03-17 09:52:50 Mar 17 12387 12397 55666.6964931 2011-04-15 16:42:57 Apr 15 12387 12397 55690.4773264 2011-05-09 11:27:21 May 09 12387 12397 55719.4218171 2011-06-07 10:07:25 Jun 07 12387 12397, 12427 55749.4273727 2011-07-07 10:15:25 Jul 07 12387 12427 55777.3971644 2011-08-04 09:31:55 Aug 04 12387 12427 55805.2782755 2011-09-01 06:40:43 Sep 01 12387 12427 55831.4115278 2011-09-27 09:52:36 Sep 27 12387 12427 55861.7244792 2011-10-27 17:23:15 Oct 27 12387 12427.12729 55888.8238194 2011-11-23 19:46:18 Nov 23 12732 12729 55919.1946181 2011-12-24 04:40:15 Dec 24 12732 12729 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 55217.7411806 2010-01-21 17:47:18 Jan 21 11882 11879,11995 55245.9193171 2010-02-18 22:03:49 Feb 18 11882 11995 55271.665787 2010-03-16 15:58:44 Mar 16 11882 11995 55299.3052778 2010-04-13 07:19:36 Apr 13 11882 11995 55327.1887963 2010-05-11 04:31:52 May 11 11882 11995 55356.4220139 2010-06-09 10:07:42 Jun 09 11882 11995,11996 55386.9642824 2010-07-09 23:08:34 Jul 09 11882 11996 55410.4907407 2010-08-02 11:46:40 Aug 02 11882 11996 55443.0433796 2010-09-04 01:02:28 Sep 04 11882 11996 55467.242419 2010-09-28 05:49:05 Sep 28 11882 11996 55497.0534375 2010-10-28 01:16:57 Oct 28 11882 11996,12384 55524.1044097 2010-11-24 02:30:21 Nov 24 12387 12384 55554.3152199 2010-12-24 07:33:55 Dec 24 12387 12384 -
MJD Date and Time Month/Day Hot Pixel Annealing ID Daily Monitor ID 54978.6171065 2009-05-27 14:48:38 May 27 anneal 11367 55018.7071528 2009-07-06 16:58:18 Jul 06 anneal 11465 55048.2918866 2009-08-05 07:00:19 Aug 05 11882 11465 55074.9377894 2009-08-31 22:30:25 Aug 31 11882 11879 55106.098287 2009-10-02 02:21:32 Oct 02 11882 11879 55132.2596991 2009-10-28 06:13:58 Oct 28 11882 11879 55160.3615394 2009-11-25 08:40:37 Nov 25 11882 11879 55186.5189699 2009-12-21 12:27:19 Dec 21 11882 11879
*The anneal originally scheduled for June 23, 2021 was missed due to the HST safing on June 13, 2021.
**An artificial anneal boundary was created on March 28, 2025, after an HST safing that day caused the WFC detectors to warm, altering the dark current distribution pre- and post-safing. The original anneal period of March 11, 2025 was thus split into two segments: March 11, 2025 to March 28, 2025, and March 28, 2025 to April 07, 2025.
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