p1t1o wrote:Might it be worth noting that the Greenwich meridian was adopted as the prime meridian in 1884, and the paris meridian (which would have been popular on french cartography before this) was about 2 degrees east of the greenwich meridian?
The line I'm taking for 0° is labeled "Colure des Equinoxes". I don't speak French, but I think it's safe to translate that to "Equinoctial Colure".
And although the numbering on the ecliptic is a little bit unclear, the fact that the numbering on the equator says "10" in one direction and "350" in the other makes me reasonably confident that the red and white stripes each represent 1°.
So I don't think I have the wrong coordinate system.
(I'm more worried about whether I've done the math correctly. Wikipedia gives star coordinates in terms of right ascension--measured in hours--and declination, whereas I'm estimating Zeta Piscium's coordinates on the globe in terms of ecliptic longitude--measured in degrees. The globe is inverted relative to the sky. And I really don't
know anything about astronomy. So someone should double-check my calculation.)