Chapter 1: Introduction

The Advanced Camera for Surveys (ACS), a third-generation instrument, was installed in the Hubble Space Telescope during Servicing Mission 3B, on March 7, 2002. Its primary purpose was to increase HST imaging discovery efficiency by about a factor of 10, with a combination of detector area and quantum efficiency that surpassed previous instruments.

ACS has three independent channels that have provided wide field, high resolution, and ultraviolet imaging capabilities respectively, using a broad assortment of filters designed to address a large range of scientific goals. In addition, coronagraphic, polarimetric, and grism capabilities have made the ACS a versatile and powerful instrument.

The ACS Instrument Handbook, which is maintained by the ACS Team at STScI, describes the instrument properties, performance, operations, and calibration. It is the basic technical reference manual for the instrument, and should be used with other documents (listed in Table 1.1) for writing Phase I proposals, detailed Phase II programs, and for data analysis. (See Figure 1.1).

In May 2009, Servicing Mission 4 (SM4) successfully restored the ACS Wide Field Channel (WFC) to regular service after its failure in January 2007. Unfortunately, the ACS High Resolution Channel (HRC) was not restored to operation during SM4, so it cannot be proposed for new observations. Nevertheless, this handbook retains description of the HRC to support analysis of archived observations. The ACS Solar Blind Channel (SBC) was unaffected by the January 2007 failure of WFC and HRC. The SBC has remained in steady operation, and was not serviced during SM4. It remains available for new observations.

Table 1.1: Useful documents

Purpose

Document or Resource

General
information and
Phase I
proposals

HST Proposal Opportunities and Science Policies, including the HST Call for Proposals and the HST Primer:
https://hst-docs.stsci.edu/display/HSP/HST+Proposal+Opportunities+and+Science+Policies

Phase II
programs

Phase II Proposal Instructions
https://hst-docs.stsci.edu/display/HPIOM
Astronomer's Proposal Tool (APT) for Phase I and II preparations
http://apt.stsci.edu/
ACS Dither Pointing Patterns
http://www.stsci.edu/hst/instrumentation/acs/proposing/dither-strategies

Data analysis

ACS Data Handbook
https://hst-docs.stsci.edu/display/ACSDHB
Drizzlepac Handbook
http://www.stsci.edu/scientific-community/software/drizzlepac.html
Space Telescope Analysis Newsletter
http://www.stsci.edu/hst/instrumentation/acs/documentation/stsci-analysis-newsletter-stan
Instrument Science Reports
http://www.stsci.edu/hst/instrumentation/acs/documentation/instrument-science-reports-isrs
Post-observation Overview
http://www.stsci.edu/hst/observing/post-observation
ACS Data Calibration and Analysis
http://www.stsci.edu/hst/instrumentation/acs/data-analysis

Instrument
specific

ACS webpage
http://www.stsci.edu/hst/instrumentation/acs

Figure 1.1:  Handbook roadmap for proposal preparation.