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 (http://www.stsci.edu/hst/HST_overview/servicing_missions). 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 surpasses previous instruments.

ACS has three independent cameras 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-WFPC2 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 Camera (WFC) to regular service after its failure in January 2007. Unfortunately, the ACS High Resolution Camera (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.

The documents in Table 1.1 can be downloaded from the ACS STScI Web site, http://www.stsci.edu/hst/acs. Paper copies can be requested by sending a message to help@stsci.edu or by calling 410-338-1082.

Table 1.1: Useful documents

Purpose	Document or Resource
General observatory information	HST Primer http://www.stsci.edu/hst/proposing/proposing/documents/primer/primer_cover.html
Phase I proposals	Proposing Overview http://www.stsci.edu/hst/proposing/docs/proposingOverview Call for Proposals http://www.stsci.edu/hst/hst/proposing/documents/cp/cp_cover.html
Phase II programs	Phase II Proposal Instructions http://www.stsci.edu/hst/programs/hst/proposing/docs/p2pi.html Astronomer's Proposal Tool (APT) for Phase II preparations http://apt.stsci.edu/ ACS Dither Pointing Patterns http://www.stsci.edu/hst/acs/proposing/dither
Data analysis	ACS Data Handbook http://www.stsci.edu/hst/acs/documents/handbooks/currentDHB/acs_cover.html MultiDrizzle Handbook v3.0 http://www.stsci.edu/hst/HST_overview/documents/multidrizzle Space Telescope Analysis Newsletter http://www.stsci.edu/hst/acs/documents/isrs/hst/acs/documents/newsletters Instrument Science Reports http://www.stsci.edu/hst/acs/documents/isrs Post-observation Overview http://www.stsci.edu/hst/Post-observation ACS Data Calibration and Analysis http://www.stsci.edu/hst/acs/analysis
Instrument specific	ACS Web page http://www.stsci.edu/hst/acs

Figure 1.1: Handbook roadmap for proposal preparation.