Two of the most important parameters affecting the efficiency of solar panels are; is the direction the panels look and the angle they make with the earth. In order to calculate these parameters, the location of the panel must be known. Because, depending on the latitude of the location, the angle of the light from the sun to the earth changes.
For example, on March 21 and September 23, the sun's rays come at a right angle to the equator, while they reach the poles at almost 0 degrees. If we take Istanbul, which is at an average latitude of 41 degrees, as a basis, it receives sunlight at an angle of about 41 degrees on these dates. And If we start from the formula we used to find the solar panel tilt angle; Latitude x 0.87 + 3.1 is about 39 degrees for this location.
Also, in the northern hemisphere the solar panel should always face south, while in the southern hemisphere it should always face north. In other words, for Istanbul, the solar panels should face towards the south, making an angle of 39 degrees with the earth. However, for higher efficiency, separate positioning for summer and winter seasons or solar-tracking panel systems can also be used.