1. Find the direction of magnetic North and consequently magnetic South.

2. Adjust for magnetic declination to find exact true South.

3. Point solar panels towards true South.

4. Find optimum tilt angle based on the latitude and the season.

Enter the value of latitude below to find the panel tilt in degrees.

**Winter**

### Latitude

**Spring and Fall**

### Latitude

**Summer**

### Latitude

Note:

1. The result above is the angle in degrees from the horizontal.

2. If you do not know the latitude of your city you can look it up here.

Phil,

These calculations work best for latitude of 25 degrees to 50 degrees.

John

For southern hemisphere users, negative latitudes give odd results.

In my first question, I asked what those other numbers mean? eg. 0.89 0.98 0.92

You also say “Enter the value of latitude below to find the antenna tilt in degrees.” – I guess a solar panel is like an antenna.

Why do I need to enter Latitude 3 times?

What are other numbers in other boxes for?

Phil,

You need to enter Latitude 3 times for the three seasons (winter, spring/autumn, summer). Usually winter is the worst in terms of solar radiation received so you may use this value. If you can change the tilt of the solar panels 4 times each year then you may use the different values for the different seasons.

John