 The solar azimuth angle can be calculated to a good approximation with the following formula, however angles should be interpreted with care because the inverse sine, i.e.or , has multiple solutions, only one of which will be correct.The following formulas can also be used to approximate the solar azimuth angle, but these formulas use cosine, so the azimuth angle as shown by a calculator will always be positive, and should be interpreted as the angle between zero and 180 degrees when the hour angle, , is negative (morning) and the angle between 180 and 360 degrees when the hour angle, , is positive (afternoon).