Last modified on 14th April 2004.
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CooC

Coordinate Conversions in Astronomy, version 2.3; March 2002

Accuracy of the Conversions

I ran several tests on galactic, supergalactic, and supergalactic cartesian conversions and found accuracy to be high. Compared with values for galaxies from literature differences were less than 0.02 degrees in the worst case and less than 0.1 % in cartesian distances. Then again, my supervisor made a remark that the inaccuracy could as well be in the coordinates I was comparing to rather than in the CooC coordinates.

Equatorial conversions were carefully studied and the inaccuracy due to precession and nutation (conversions from one epoch to another) was found to be approximately 1.5 s in R.A. (maximum errors were about ±3.5 s) and approximately 8" in declination (maximum errors were about ±20"). Significant correlation between amount of error and coordinates was not found except very close to the celestial poles (dec. > 88° or < -88°), where errors were highest.

Ecliptic conversions still need more examination and horizontal conversions are currently quite unreliable (this message will be removed as soon as the latest bug has been corrected).

Created by Rami T. F. Rekola
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