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Manuscript Title: Programs "CELESTE" and "STELLA" for computations in special relativity: evaluation of the celestial view from an interstellar spacecraft.
Authors: E. Sheldon, R.H. Giles
Program title: CELESTE AND STELLA
Catalogue identifier: AACI_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 29(1983)269
Programming language: Fortran.
Computer: CDC CYBER 71.
Operating system: FORTRAN-IV EXTENDED (ANSI 1966).
RAM: 22K words
Word size: 60
Keywords: Astrophysics, Stars, Astroscape, Starscape, Star plot, Celestial view, Special relativity, Length contraction, Time dilation, Aberration, Parallax, Doppler effect, Doppler shift, Brightness, Apparent magnitude, Stellar temperature, Spectral type, Colour Bolometric correction, Spaceflight, Interstellar travel, Astronavigation.
Classification: 1.7.

Nature of problem:
CELESTE (batch-processing version) and STELLA (time-sharing terminal version) have been compiled to evaluate the celestial fore and aft views from a spacecraft in relativistic motion, aimed in any specified direction and located at any given distance from the solar system (i.e. , Earth). The calculations take account of the special-relativistic effects of space contraction, aberration, parallax, Doppler shift of wavelength (colour) (including shift of infra-red stellar sources into the visible region), and perceived brightness (i.e., apparent visual magnitude). The output may, at option, provide a printed astroscape diagram as well as a tabulation of numerical results. The output data may be fed to a colour display console for a direct visual display.

Solution method:
Using special-relativistic formulae, the programs convert input data for stars, e.g., visible and infra-red sources (stellar coordinates, distances, spectroscopic class, apparent visual and infra-red magnitudes) into a polar representation of the fore and aft view as a function of craft speed and direction and distance.

Restrictions:
While the programs have been designed to deal with infra-red as well as visible stellar sources, including appropriate bolometric corrections to determine the apparent visual magnitude (perceived brightness), they do contain similar procedures for ultra-violet sources (since at present only piecemeal data on these are available). The input file for stellar data has been restricted to stars of 4th magnitude or brigther, in order to keep the length of the star catalogue to below 5500 entries. It could, however, be expanded at will. The programs do not provide side views, but could readily be modified to furnish these if desired.

Running time:
Less than 1 min in batch mode; 2-3 min in interactive-terminal mode when no plots are generated, 5 min in terminal mode with plots.