Forecast.Solar

For HomeAssistant you can use in both cases the determined azimuth value as is, for direct API calls you must convert it according to the convention:

azimuth = azimuth - 180

• Go to Open Street Map Compass
• Click Draw single leg route
• Find your location and zoom in as far as possible
• Click Show compass
• Move and rotate the compass in place, north is always at the top of the map
• Get your azimuth (upper right corner), for me abt. 172°

• Go to SunCalc
• Find your location (input upper left) and zoom in as far as possible, north is always at the top of the map
• Switch the map to “OSM” (on the map top right)

• Click on a suitable corner of your building
• Draw the time at the top so that the sun falls vertically on your modules …

• … to get a view like this

• Find your azimuth on the left: