Emerald Mauna Loa

A simulation of a mechanical watch face with a variety of astronomical info

This app will no longer be available as of November 1, 2023, as Emerald Sequoia LLC is shutting down. Please see our blog post linked from our support page listed here.

The WearOS watch face Mauna Loa is a simulation of a mechanical astronomical analog watch face, showing a variety of information.

The outer 24-hour dial moves like that on Emerald Mauna Kea except in this case it has the time of the Moon's meridian transit at the top ("Moon-noon"). Unlike solar noon, this changes by about an hour each day and moves all around the clock. The small gray Moon disk on the outer ring indicates the current 24-hour time. The gray semi-circles mark the times of moonrise and moonset; the most recent event (rise or set) and the next event are shown.

The large moon image at 6 o'clock shows the Moon's current phase, in a display like Emerald Chandra's.

The dial at 10 o'clock shows the local apparent solar time (sundial time for the current longitude). The local apparent sidereal time is shown in the dial at 2 o'clock. The green triangle indicates UTC.

In ambient mode, the same information is displayed, but with different colors to save energy.

No network access is required; only the device time and location are used internally.

More information is available at the listed website.