Handbook Structure

The ACS Data Handbook is organized in five chapters, which discuss the following topics:

• Chapter 1 - ACS Overview describes the ACS capabilities, design, and basic instrument operations; detailed information can be found in the ACS Instrument Handbook.

• Chapter 2 - ACS Data Structure describes the ACS file structures, image header keywords, and data file sizes.
• Chapter 3 - ACS Calibration Pipeline describes the processing and flow of data from the STScI Archive. There are two major components:
  • calacs, the standard ACS calibration software, has undergone significant updates that include corrections to post-SM4 WFC image artifacts. In addition, the software generates two sets of calibrated products: one with standard calibrations and another set with pixel-based CTE corrections.
  • AstroDrizzle creates images corrected for geometric distortion, and combines associated images with cosmic ray rejection. (Please refer to the DrizzlePac web page for details.)

This chapter also provides instructions on how to run calacs manually.

• Chapter 4 - ACS Data Processing Considerations describes how various instrument characteristics affect data processing.
• Chapter 5 - Data Analysis describes the data reduction software available to work with ACS data, and specific analysis strategies for imaging, spectroscopy, polarimetry, and coronagraphy data.

For the latest information regarding ACS performance and calibration, users are advised to consult the ACS webpage.