Starlink Project
Starlink User Note 139.18

Peter W. Draper, Mark Taylor, Alasdair Allan

7 July 2011

CCDPACK – CCD data reduction package

Version 4.0

Users’ Manual


CCDPACK is a package of programs for reducing CCD-like data. They allow you to debias, remove dark current, flatfield, register, resample and normalize data from single- or multiple-CCD instruments.

CCDPACK is designed to help you to reduce your data easily. The basic reduction stages can be set up using an X based GUI that controls an automated reduction system. The GUI is designed to allow you to start working without any detailed knowledge of the package (or indeed of CCD reduction). Registration is performed using graphical, script based or automated techniques that help reduce the amount of work to a minimum.

This document is intended for all users of CCDPACK. It provides instruction in how to use CCDPACK, describes CCD reduction in general and contains complete descriptions of the individual programs.


1 Introduction
2 Starting up CCDPACK
 2.1 Getting Help
 2.2 Running from the C-shell
3 Demonstrations and test data
4 Basic principles of CCD data reduction
5 How to reduce your data now
 5.1 Using the CCDPACK data reduction GUI
  5.1.1 GUI problems
 5.2 Command-line reduction
6 Data formats
7 Using the data reduction programs
 7.1 Using the automated processing facilities directly
  7.1.1 Package configuration
  7.1.2 Setting reduction information
  7.1.3 Reduction extension items
  7.1.4 Scheduling a reduction
  7.1.5 Scheduling from a script
 7.2 Using the CCDPACK programs to reduce data
  7.2.1 Step 1 - Setting up
  7.2.2 Step 2 - Making a bias calibration frame
  7.2.3 Step 3 - Debiassing
  7.2.4 With a master bias
  7.2.5 Without a bias frame
  7.2.6 Other DEBIAS functions
  7.2.7 Step 4 - Flash or dark calibration
  7.2.8 Step 5 - Flatfielding
  7.2.9 Example scripts
  7.2.10 Schematic reduction sequence
 7.3 IR data reduction
8 Registration and mosaicing
 8.1 The registration process
  8.1.1 More about attached coordinate systems
 8.2 Object matching and position lists
  8.2.1 Determining transformation parameters
  8.2.2 Automated registration
  8.2.3 Semi-automated registration
  8.2.4 General linear transformations
  8.2.5 Using position lists
 8.3 Handling coordinate systems directly
 8.4 Re-use of coordinate system information with AST files
 8.5 Combining coordinate systems
 8.6 Viewing image alignment
 8.7 Data resampling
 8.8 Mosaicing and normalisation
 8.9 Combination by drizzling
 8.10 Some registration examples
  8.10.1 Registering images with SKY coordinates
  8.10.2 Registering frames from a mosaic camera
  8.10.3 Example AST file
 8.11 Schematic registration sequences
9 Set processing — multiple image instruments
 9.1 Adding Set headers
  9.1.1 Grouping by explicit list
  9.1.2 Grouping by container
  9.1.3 Splitting a single image into multiple sections
  9.1.4 Set alignment (CCD_SET) coordinates
 9.2 Removing Set headers
 9.3 Examining Set headers
 9.4 Global parameters with Sets
 9.5 Using Sets in reduction tasks
 9.6 Using Sets in registration tasks
 9.7 Some examples of Set use
  9.7.1 Data reduction of frames from a mosaic camera
  9.7.2 Registering frames from a mosaic camera
10 Parameter behaviour and control
11 Background processing
12 The CCDPACK logging system
 12.1 Writing your own comments to the log file
13 Processing lists of data
 13.1 Input wildcards
 13.2 Indirection
 13.3 Output names
14 Bad data masks (ARD)
15 Acknowledgements
16 Acknowledging this software
A Notes for IRAF users
B Description of the CCDPACK routines
 B.1 General considerations
  B.1.1 Data saturation
  B.1.2 Data types and sizes
  B.1.3 Image combination techniques
 B.2 Alphabetic list of CCDPACK routines.
 B.3 Complete routine descriptions
ASTEXP– Exports coordinate system information from images
ASTIMP– Imports coordinate system information into images.
CALCOR– Subtracts a scaled dark or flash calibration image from a series of images
CCDALIGN– Aligns images graphically by interactive object selection
CCDCLEAR– Clears CCDPACK global parameters
CCDEDIT– Edits CCDPACK image extensions
CCDFORK– Creates a script for executing CCDPACK commands in a background process
CCDNDFAC– Accesses a list of images and writes their names to a file
CCDNOTE– Adds a note to the current CCDPACK log file
CCDSETUP– Sets the CCDPACK global parameters
CCDSHOW– Displays the value of the CCDPACK global parameters
DEBIAS– Performs the debiassing and initial preparation of CCD data
DRAWNDF– Draws aligned images or outlines on a graphics display
DRIZZLE– Resamples and mosaics using the drizzling algorithm
FINDCENT– Centroids image features
FINDOBJ– Locates and centroids image features
FINDOFF– Performs pattern-matching between position lists related by simple offsets
FLATCOR– Divides a series of images by a flatfield
IDICURS– Views and writes position lists interactively
IMPORT– Imports FITS information into images
MAKEBIAS– Produces a master from a set of bias frames
MAKECAL– Produces a dark or pre-flash calibration image
MAKEFLAT– Produces a flatfield calibration image
MAKEMOS– Make a mosaic by combining and (optionally) normalising a set of images
MAKESET– Writes Set header information to images
PAIRNDF– Aligns images graphically by drag and drop
PLOTLIST– Draws position markers on a graphics display
PRESENT– Presents a list of images to CCDPACK
REDUCE– Automatic CCD data reduction facility (command-line version)
REGISTER– Determines transformations between lists of positions
SCHEDULE– Schedules an automated CCDPACK reduction
SHOWSET– Outputs image Set header information
TRANLIST– Transform lists of positions
TRANNDF– Transforms a list of images by resampling
WCSEDIT– Modifies or examines image coordinate system information
WCSREG– Aligns images using multiple coordinate systems
XREDUCE– Starts the automated CCD data reduction GUI

C Using TRANSFORM structures for registration
 C.1 Handling TRANSFORM structures
 C.2 Transforming position lists
D Memory requirements
E A glossary of CCD terminology
 E.1 The bias level
 E.2 Readout-noise
 E.3 Bias strips
 E.4 ADC factor
 E.5 Saturation
 E.6 Dark current
 E.7 Pre-flashing
 E.8 Flatfielding
 E.9 Fringing
F Changes
 F.1 Release 2.0
 F.2 Release 2.0-2
 F.3 Release 2.1
 F.4 Release 2.2
 F.5 Release 2.2-1
 F.6 Release 2.3-0
 F.7 Release 2.3-1
 F.8 Release 2.4-0
 F.9 Release 3.0-0
 F.10 Release 3.0-1
 F.11 Release 3.1-0
 F.12 Release 3.1-1
 F.13 Release 4.0-10
 F.14 Release 4.0-11
 F.15 Release 4.0-12
 F.16 Release 4.0-14
 F.17 Release 4.0-15
 F.18 Release 4.0-16
 F.19 Release 4.0-17
 F.20 Release 4.0-18
 F.21 Release 4.0-19
 F.22 Release 4.0-20
G Backpage alphabetic listing
H Backpage alphabetic listing