- #1
JeffOCA
- 49
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Hi,
1/ The ecliptic plane is tilted at a constant angle (23,45°) as compared to the celestial equator. So, why the angle between ecliptic and equator is +23,45° at spring equinox and -23,45° at autumnal equinox ?
2/ On this document, ε = 23°27'. Why don't we have ψ = ε = 23°27' ? The equator circle and the little circle (which passes through the Sun S and is parallel to equator) cross the ecliptic at a constant angle 23°27' ?
Thanks for helping
1/ The ecliptic plane is tilted at a constant angle (23,45°) as compared to the celestial equator. So, why the angle between ecliptic and equator is +23,45° at spring equinox and -23,45° at autumnal equinox ?
2/ On this document, ε = 23°27'. Why don't we have ψ = ε = 23°27' ? The equator circle and the little circle (which passes through the Sun S and is parallel to equator) cross the ecliptic at a constant angle 23°27' ?
Thanks for helping