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wymarc / astrolabe-generator

A Java-based tool for generating EPS files for constructing astrolabes and related tools
GNU General Public License v3.0
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Axial precession #3

Closed fsignoret closed 4 years ago

fsignoret commented 4 years ago

Hello,

I don't know if that has any impact on the usage of the astrolabe, but it seems it does not reflect the position of the sun as today, taking into account the axial precession.

Would it be possible to handle that?

Thanks! Regards, Florian

fsignoret commented 4 years ago

After thinking about it again, I confirm that there is no impact using the zodiac constellations without fixing the axial precession (apart from the philosophical point of view). Indeed, what is important is that the position of the sun on the ecliptic is eventually the correct one.

This would not be the case for the star positions, though, but I double checked, and the axial precession is being taken into account for these ones.

So, instead of a defect, this would rather be an enhancement proposition, to give the option to use the 13 constellations (instead of the 12), taking into account axial precession and the real size of constellations (as it is done on http://www.astrosurf.com/spheres/as/astrolabe.htm)