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LEXT manual

LEXT REFERENCE MANUAL

Nial Tanvir

This document describes the LEXT software package developed to support the LDSS-2 instrument at the WHT. It provides facilities to design multiaperture masks, acquire the target field and reduce the resultant data.

This version differs from the original AAT LEXT (originated by Richard Hook) in several respects. Most notably, data access is now done using DSA routines, and hence both the FIGARO/DST and NDF/SDF images are now supported data formats. There are new routines to support the LDSS-2 convention for specification of masks, field acquisition procedure and data reduction. In addition there are a large number of minor enhancements, such as the propagation and use of FITS header information, improved arc-line fitting, improved sky-subtraction, more examination and filter options. Finally the LEXT procedure language has been enhanced to allow considerably more powerful procedures.

• Introduction
• Description of the user interface
  • LEXT procedures
  • Access to the operating system
  • On-line HELP.
  • Ending a LEXT session
• The internal data stack
  • Lists
  • Images
  • Creating lists and images internally
  • Mode of operation
  • Manipulating the data stack
  • Slot status
  • Slot protection
  • Startup file
• Internal parameters and header information
  • Examining and saving parameter settings
  • Interface options
  • Instrumental parameters
  • Mask parameters
  • Plotter parameters
  • Telescope parameters
• Data import and export
  • Object catalogues
    • Coordinate entries
    • Keyword entries
• Mask manufacturing tools
• Target acquisition tools
• Mapping focal plane to detector coordinates
• Data processing
  • Simple Image processing
  • Simple List processing.
  • Examination and manipulation of data
  • More sophisticated image processing
• Graphical output
  • Image display devices
  • Displaying images
  • Plotting List information
  • Defining a region of interest
  • Interactive examination of data
• Spectrum extraction and calibration
  • Flatfielding
  • Arc subpackage
    • ARC command interface
  • Using the Extract command