[Kstars-devel] Eclipse tool

[Daniel Baboiu]

KStars needs a proper Eclipse/Occultation tool. (yes, I'm offering to
implement these)

Currently, these events can be predicted to some degree with the
Conjunction tool (for solar eclipses and occultations), which also does
oppositions (for moon eclipses). However, this is rather crude, and only
predicts the moment of smallest separation; sufficient in most cases to
predict if an event occurs. For example, on 4 April 2015 at 11:45AM UT
there is an opposition between Sun and Moon, with separation of 13'43".

But this in not sufficient for more than a qualitative estimation. A
long time ago I went through the calculations for Moon eclipses, and got
external and internal contacts with umbra and penumbra within 2 minutes
of the officially published time in Astronomical Almanacs, even though I
only used something like 5 terms for the Sun and 13 for the Moon. Once I
got the coordinates, it is something like half a day of work to fully
implement the algorithm. but it is not a beginner's job, as it needs
some understanding of the phenomena.

Since then, I went through the calculation for the Solar eclipses,
although I didn't get to the implementation part.