This is an unconventional clock concept, with a North Pole-centered azimuthal world map that rotates counterclockwise once per day, just like the Earth does around its axis when viewed from the north. This makes it possible to see roughly what time it is everywhere on Earth at once. The clock hand is the central longitude of your time zone.

The star map is also shown, in the same projection, as an overlay. The Sun, Moon and planets are also shown, with accurate ecliptic longitudes to within 1 degree max error, but with their ecliptic latitudes ignored – that is, they are snapped to the ecliptic circle for a cleaner look. The star map makes one clockwise rotation once every year, so that the Sun stays roughly at the top of the watch face.

Since the clock's direction is counterclockwise, the hour hand will point right in the morning, up at mid day, left in the evening, and down at night. This takes some getting used to, but in my opinion, this is the direction clocks ought to go, since it makes it possible to have this kind of a clean, map-based world clock. The reason clockwiseness is the way it is has to do with sundials, which flips things relative to how the Earth actually moves.

The positions of the Sun, Moon and planets are where you see them in the sky. This means that if you can identify one celestial object, you can see on the watch face where to expect the others. E.g. if the Moon is up, and you see on the clock that Jupiter is supposed to be 90 degrees to its left, you should be able to see it if you turn 90 degrees left from looking at the real Moon – given that it is above the horizon. There is no horizon indicator on the Wear OS watch face, but there is at the bottom of the explanation page, so you can get a rough idea of what you can expect to be above the horizon.

The motivation and hope for this watch face is to reconnect timekeeping with the astronomical events it really is about, and also have it be a constant reminder on your wrist to look up and learn to identify planets and stars. We live inside this beautiful celestial sphere that we spent millennia figuring out, but then lost contact with because of mechanical clocks, various abstract timekeeping conventions, and artificial light.

The website contains a thorough explanation of how to read the clock, with visualizations, as well as two long articles, one about astronomy, with a lot more interactive visualizations, and one about the history of astronomical timekeeping. If you don't have a Wear OS, you might still find these interesting reads.