Sky Sources' Positional Errors
Joachim Köppen Kiel April 2017

A celestial source moves over the sky, making a trajectory in azimuth and elevation. If for some reason, its predicted celestial coordinaties (Right Ascension and Declination) are only approximately known or have an error, this would cause to show up as offsets in azimuth and elevation. The dependence of these deviations - as a function its position in the sky - can tell about the errors in its celestial coordinates.
This script allows to compute and display the azimuth/elevation offsets for given errors in right ascension and declination. This is done for a given latitude of the observer and the true declination of the source. In the grey parts of the curve the source is below the horizon.
In the Az-El plot the red curve shows the measured sky path, and the black lines indicate the difference to the true path.

Observer latitude [deg]:

True Declination [deg]:

Offset in Right Ascension [deg]:
Offset in Declination [deg]:

X =
Y =

Mouse position:

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