Ask Lemmy

There's algorithms that can get sun and moon (and really any celestial body's) relative position to some place on earth. They don't need internet connections. They just need historical data, a location, and a time. The latter of the two can be gotten from GPS. Something that can process a few thousand floats per second should be enough processing power.

Honestly it sounds like home assistant could be useful to you, if you have the time to tinker. Definitely can build rules based on sunset times.

In order to calculate an accurate sunrise and sunset time, you need the following variables to be known.

• The current day
• The current time (if you want to know the time delta for when it rises and sets)
• The current location

Also, we need to consider that NTP sends the time in UTC, and the timezone offset calculation is done by the endpoint.

Even if you know the timezone your in, it still doesn't provide the exact position you need to accurately determine when the sun will rise and set.

Sensorwatch has a sunset/sunrise face https://github.com/joeycastillo/second-movement/blob/main/lib/sunriset/sunriset.c

If you dig into it, see if you can fix this issue that I created months ago: https://github.com/issues/created?issue=joeycastillo%7Csecond-movement%7C55

Edit: actually, if you're doing this as a psych experiment, just buy a sensor watch and make a custom face for it. It'd be a great way to publish your findings.

If you start living by your own time you should take a look at decimal time too.

https://github.com/dmkishi/Dusk2Dawn