> for observable comets and use them in Guide you could try to experiment
> with the third and second last entries for this comet (13.0 and 4.0). These
> determine the brighness of a comet with changing distances from the sun
> and earth. But don't ask me for the formulae.

The formula is
m= Mo + 5 * log (delta) + 2.5 * n * log r
In this example, m0=13.0, and n=4.0

With comets in outburst these power-law formular tend to fail.
However, if you do not have an adequate info you can
set n=4 (typical value), and solve for Mo. Delta is the
distance earth comet in a.U. and r the sun-comet distance.


Hartwig






H. Luethen
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