Azimuth is the compass direction your solar panels face
Declination is the angle difference between true north and magnetic north
Use a compass app or GPS-based solar app to find panel azimuth
Stand in front of the panels and read the direction they face
Measure azimuth in degrees from true north, clockwise
Use a site survey tool, satellite map, or solar design software for more accurate azimuth
Check whether your compass app is showing magnetic north or true north
If it shows magnetic north, convert to true north using local magnetic declination
Get local magnetic declination from NOAA or a geomagnetic declination calculator
Add or subtract the declination value based on your location and compass reading
Use a clinometer, inclinometer, or solar app to measure panel tilt if needed
If you meant solar declination, use the date and solar position calculator for that value
Solar declination changes daily and is not the same as panel azimuth
For rooftop systems, measure the facing direction of the roof plane where panels are installed
For ground mounts, measure the direction the panel surface points directly
Compare measurements with utility bills, inverter data, or system design documents if available