[liftm]

You're forgetting about orientation (and altitude)? The observed position also varies a bit with air pressure and temperature, but iirc that's less than a few degrees. Anyway, you grab yourself a nice ephemeris library like skyfield, do a little bit of your_location.at(now).observe(sun).apparent().altaz('standard'), and there's your angles.

The trickiest part might be getting an accurate time on whatever cheap controller your using.

[hawski]

Radio time signal stations broadcast time and I would hope it would be cheap enough as we have radio controlled clocks, that do not cost a fortune. Otherwise a small battery and a RTC would be enough and probably a better solution.

[sgtnoodle]

A GPS receiver can be had for like $15 these days. That will give you time and position, and require less maintenance than an RTC.

Of course, a $15 receiver might not have the best sensitivity, so reception might actually be a practical concern. On the other hand, you only need 4 satellites for a coarse fix, and you could seemingly tolerate a many minute cold fix time.