I've seen the solar noon formula described as snoon = 720 – 4*longitude – eqtime. I'm curious if it is equally reliable within a relatively small margin of error (+-60 seconds) to simply get the midpoint between sunrise and sunset, given that data is already calculated and available.

Is there any occasion when solar noon wouldn't be equal time from sunrise and sunset, give or take the aforementioned margin of error?

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    $\begingroup$ I'm voting to close this question as off-topic because it is crossposted to Astronomy.SE, where it is a better fit and got an answer (astronomy.stackexchange.com/questions/22239/…) $\endgroup$ – Jan Doggen Aug 22 '17 at 7:28
  • $\begingroup$ Good question (and those not familiar with what eqtime is, this Astronomy StackExchange question discusses it some). I would think that'd be just fine, but can't prove it. I believe I had a textbook that discusses it further, but not near right now. $\endgroup$ – JeopardyTempest Aug 22 '17 at 15:55
  • $\begingroup$ That's what I get for leaving it open since yesterday and just now adding the comment. Boo crossposting! :-D $\endgroup$ – JeopardyTempest Aug 22 '17 at 15:56

Received an answer on the astronomy stack. https://astronomy.stackexchange.com/questions/22239/getting-solar-noon-from-sunset-and-sunrise/22241#22241

The short of it is that yes, this is reasonably accurate for most geographies, but can vary significantly in polar regions. For most cases, middling the difference of sunrise and sunset is sufficient.

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