Check or build a sundial
Utility that calculates a sundial Vertical declination or not (or see an existing one), dynamically. It provides results of Latitude, Longitude, Geographic Location and drawing angles for each hour of the day they are visible to a given orientation.
When you have the desired calculation, you can save an image by touching the screen, you can then share or use to make our watch.
It shows that the solar time is as valid as that of our watches.
It works in the northern hemisphere.(and from now on, also in the southern hemisphere)
If you're a fan, you need it.
When you start, you may need to calibrate the sensors, waving the device in various directions.
Avoid use near magnetic sources.