3 ms·

I'd be curious if there's a trick to doing this (or aproxamitly) without relying on the Equinox.

• ColinWright 8y ago
  It's not a trick, you can do it, but the geometry and the calculations are more complicated. At Equinox we don't have to know or worry about the axial tilt. Away from Equinox we do have to both know it and use it. It's not hard, but there's a lot more too it, so it starts to lose its elegance and simplicity.
  • nixpulvis 8y ago
    Well yea, I know it can be done... thanks cpt obvious. Now please downvote me to hell for being an asshole.
• nixpulvis 8y ago
  Also, I believe if we're being pedantic, this causes issues: > However, because the Moon (and to a lesser extent the other planets) cause the motion of the Earth to vary from a perfect ellipse, the equinox is now officially defined by the Sun's more regular ecliptic longitude rather than by its declination. The instants of the equinoxes are currently defined to be when the longitude of the Sun is 0° and 180°.[4] There are tiny (up to 1¼ arcsecond) variations in the Sun's latitude (discussed below), which means the Sun's center is rarely precisely over the equator under the official definition. The two understandings of the equinox can lead to discrepancies of up to 69 seconds. https://en.wikipedia.org/wiki/Equinox https://en.wikipedia.org/wiki/Equinox
  • ColinWright 8y ago
    Yes indeed - "Equinox" us being used here as a shorthand for "the date that makes this work, which is roughly Equinox, but might be a little different". The differences are small, there are larger error margins elsewhere in the calculations as given. It's an interesting exercise to start to chase these down and make this as precise as possible, but that wasn't the purpose of the post.