Thanks to @bleeptrack's suggestion, i now have an e-ink lunar-phase display on a twenty-four hour analog watch.
In addition to the lunar phase, the e-ink watch shows daylight hours and solar noon, as well as the upcoming moon-rise and set times. Source code: https://github.com/osresearch/moon-watch
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Now with a text mode for when you want the exact moment of location and altitude adjusted celestial events.
@th oh wow I didn't realise that someone was finally making a decent smartwatch now.
@th Must say, your watch looks gorgeous!