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Comment by franze

2 days ago

my modern equivalent(I needed last year for surfing (after i needed to cut a surf trip short as it became night))

https://daylight.franzai.com/

With your app, it seems daylight today in Chicago is the same length as yesterday's solstice, although it starts and ends 30 seconds later.

today - 07:18:59 → 16:24:29 = 9:5:30. yesterday - 7:18:23 → 16:23:53 = 9:5:30

  • Sunrise and sunset aren't in phase (or exactly out of phase). The latest sunrise and the earliest sunset don't happen on the same day and neither happens on the solstice. Not at this northern latitude anyway.

and yes, the maths fails when you are super super high north or south

  • Hey! nice little useful web page. I like the minimalism of it.

    Does the math fail because of not considering (i) equation of time and (ii) oblateness of the Earth ?