1. HST Call for Cycle 32 Bridge Programs with ACS/WFC and WFC3/IR

STScI is offering a special HST observing opportunity to the astronomy community to propose for "Bridge Programs" with ACS/WFC and WFC3/IR, in anticipation of likely operational changes in Cycle 33 due to budgetary constraints. Specifically, it is unlikely that ACS/WFC and WFC3/IR will be available for new observing programs in Cycle 33 and beyond.

Proposals for “Bridge programs” must meet one of the following selection criteria:

1. The science goals can only be achieved through observations with ACS/WFC or WFC3/IR; e.g. the source is too bright to allow infrared observations with JWST, or the observations require a technical capability (filter, mode) that is only available with ACS/WFC or WFC3/IR.
2. The proposed observations will contribute significantly to transitioning science programs or areas from ACS/WFC or WFC3/IR to other instruments. These might include, for example, cross-calibration measurements.

The ACS team would like to remind the community of the unique observing modes that are available on the ACS/WFC beyond broad-band/narrow-band imaging. They are as follows with corresponding links to relevant documentation (e.g., ACS Data Handbook (DHB), ACS Instrument Handbook (IHB), or a journal article):

1. Ramp Filters (Details in the DHB)
2. Optical Grism Spectroscopy (Details in the DHB and IHB)
3. Imaging Polarimetry (Details in the IHB and DHB)
4. Imaging Spectro-Polarimetry (Details in the IHB and RNAAS article)

We highly encourage the community to apply for observing time to use these unique observing modes while they are available.

Please also refer to the contemporaneous WFC3 STAN (October 2024), to obtain detailed information on the unique observing modes of WFC3/IR that will no longer be available after the Cycle 32 Bridge Programs.

Proposals should be submitted as Cycle 32 GO programs using the Astronomer’s Proposal Tool (APT) by Thursday November 7 2024 at 8:00pm Eastern time. 

Full details about the proposal requirements are included in the Cycle 32 Bridge Program Call.

2. Serial CTE Correction coming to CALACS

A pixel-based serial (X-direction) CTE correction for ACS/WFC will be included in CALACS version 10.4.0 as part of hstcal version 3.0.4, planned for release in the next few months. Both serial and parallel (Y-direction) CTE corrections will run by default with this new version of CALACS. Full details of the serial CTE correction will be provided in a forthcoming ACS ISR.

3. Recent Instrument Science Reports

For a complete list with abstracts, please visit the ACS ISR webpage.

• ACS ISR 2024-06 “Implementing an Ubercal Model for ACS/WFC” (Ryan, Bellini, and Cohen)
• ACS ISR 2024-05 “Glint in ACS/WFC Imaging Data” (Mehra, Stark, and Grogin)
• ACS ISR 2024-04 “Updates to the SBC Dark Rate Monitor” (Guzman and Avila)
• ACS ISR 2024-03 “The Evolution of Post-SM4 Bias Striping Noise in the ACS/WFC” (McDonald and Grogin)
• ACS ISR 2024-02 “The Impact of CTE on Point Source Detection in Simulated ACS/WFC Imaging Data” (Stark and Grogin)
• ACS ISR 2024-01 "Evolution of Sink Pixels in ACS/WFC and Connection to Charge Transfer Efficiency” (Guzman and Ryon)