Instrument Design

The Advanced Camera for Surveys (ACS) employs two fundamentally different types of detectors: Charge-coupled device (CCD) for use from the optical to the near-IR, and a Multi-Anode Microchannel Array detector (MAMA) for use in the ultraviolet. The CCD and the MAMA detectors are used in different ways and impose their own unique limitations on the feasibility of observations performed with them. The ACS is a third generation HST instrument and includes two operating channels, Wide Field Channel (WFC) and Solar Blind Channel (SBC). The High Resolution Channel (HRC) is inoperative. The specifications for all three are listed in the table below.

The ACS optical design incorporates two main optical channels: one for the WFC, and one which is shared by the HRC and SBC.

• ACS/WFC Optical Path
• ACS/HRC and ACS/SBC Optical Path
• HST Field of View Configuration

Instrument Characterization and Documentation

For a high-level description of the ACS detectors please refer to Chapter 3 in the ACS Instrument Handbook (ACS IHB) or Chapter 1 in the ACS Data Handbook (ACS DHB). For an in-depth description of the ACS detectors please refer to the following chapters of the ACS IHB:

WFC and HRC CCD Detectors

• CCD Characteristics: Chapter 4.2
• CCD Operations and Limitations: Chapter 4.3

SBC MAMA Detector

• MAMA Characteristics: Chapter 4.4
• MAMA Operations and Limitations: Chapter 4.5
• Bright Object Limits: Chapter 4.6

System throughputs for all three ACS channels can be computed for any date using stsynphot. Interactive throughput plots, bandpass summary tables, and example code for using stsynphot can be found below.