CCDPACK – CCD data reduction package

SUN/139.18

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

Abstract

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.

Contents

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