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Comment by robryk | Hacker News Reader

I don't get how one can get realistic modeling of eclipses without taking into account the eccentricity of Earth's orbit around the Sun (it not only minorly affects the distance, but more imporantly it causes the angular speed of Earth around the Sun to vary).

Am I overestimating the impact of that error, missing a description of how it was accounted for, or something else?

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Isn't the earth's eccentricity incredibly low? (To the point that human-noticeability or non-precision-machinability are out of the question?)

That's not to say I have any comment on the accuracy of ellipse calculation. Keplerian mechanics are beyond me. But I did see a the gear-ratio calculation repo linked: https://github.com/amandaghassaei/tellurion-orrery/tree/main...

It seems angular positional error after 100 years of simulation was the optimization goal.

> Isn't the earth's eccentricity incredibly low? (To the point that human-noticeability or non-precision-machinability are out of the question?)

It's one-percentish, and causes the length of time between equinoxes to be shorter on the northern-hemisphere-winter-side by a day or so. The date scale on the model includes single-day divisions, which made me think that such accuracy was intended; perhaps I was wrong in that.

My intuition is that that would affect the location of the eclipse track across the earth, but that it’s not enough to significantly shift the date of the eclipse since that’s more determined by the moon’s location.

You might be able to compensate for that in the calendar track?

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