I was curious how the times were obtained. It uses https://github.com/nathan-osman/go-sunrise , which links to this calculation method: https://en.wikipedia.org/wiki/Sunrise_equation#Complete_calc...
replies(1):
Now I've written a terminal app for this (Mac/Linux)
Features: a colorful summary of daylight times for your location; projected change over the coming days; handles NO_COLOR and a ---short flag if you dislike the output format.
The location is IP-based but you can override this if you're on a VPN. Just create a terminal alias with the --loc flag. The app supports areas in the arctic / antarctic circle too.
Check our the repository for a preview and instructions on how you can install it with Homebrew.
(There is a Windows build but it's not yet tested)