Representations of spectral coordinates in FITS

E. W. Greisen; M. R. Calabretta; F. G. Valdes; S. L. Allen

doi:10.1051/0004-6361:20053818

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arXiv · astro-ph/0507293

Representations of spectral coordinates in FITS

E. W. Greisen·M. R. Calabretta·F. G. Valdes·S. L. Allen

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Abstract

Greisen & Calabretta describe a generalized method for specifying the coordinates of FITS data samples. Following that general method, Calabretta & Greisen describe detailed conventions for defining celestial coordinates as they are projected onto a two-dimensional plane. The present paper extends the discussion to the spectral coordinates of wavelength, frequency, and velocity. World coordinate functions are defined for spectral axes sampled linearly in wavelength, frequency, or velocity, linearly in the logarithm of wavelength or frequency, as projected by ideal dispersing elements, and as specified by a lookup table.

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E. W. Greisen, M. R. Calabretta, F. G. Valdes, S. L. Allen. 2005-10-07. Representations of spectral coordinates in FITS. https://doi.org/10.1051/0004-6361%3A20053818

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