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Wavelength arrays

Figaro tries to hold wavelength information in as general a way as possible. If a file called, say, `spect' contains a wavelength-calibrated spectrum, then there will be two data arrays in the structure held in the file. The main data array will be an array containing the actual spectrum, and the X-axis array will be an array of related size containing the wavelength information.

Each element of the X-axis array contains the wavelength value for the corresponding element of the spectrum-that is, for the centre of the corresponding data bin. For uncalibrated data, the X-axis array will usually not exist.

The `hdstrace' command may be used to examine elements of either the data or wavelength arrays, and the `ilist' command can be used to tabulate them.



next up previous 79
Next: The `arc' command
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Previous: Discrete and continuous channel numbers

FIGARO A general data reduction system
Starlink User Note 86
Keith Shortridge, Horst Meyerdierks,
Malcolm Currie, Martin Clayton, Jon Lockley,
Anne Charles, Clive Davenhall,
Mark Taylor, Tim Ash, Tim Wilkins, Dave Axon,
John Palmer, Anthony Holloway and
Vito Graffagnino
2004 February 17
E-mail:ussc@star.rl.ac.uk

Copyright © 2010 Science and Technology Facilities Council