Understanding the Position of the Sun at Noon

The Sun's Location at Noon

At noon, the sun is generally at its highest point in the sky for a given location. However, its position varies depending on the time of year and one's geographical location. This article will explore the nuances of the sun's position at noon and the related concepts of solar altitude, indicating how to calculate the sun's position using the solar altitude formula.

Equator

At the equator, the sun is directly overhead at noon during the equinoxes, specifically around March 21 and September 23. The time of the year influences whether the sun is leaning towards the northern or southern equator.

Northern Hemisphere

In the northern hemisphere, the sun is at its highest point in the southern part of the sky at noon during the summer solstice, around June 21. Conversely, as we approach the winter solstice, around December 21, the sun's trajectory moves lower in the sky.

Southern Hemisphere

The opposite is true for the southern hemisphere. Here, the sun is at its highest in the northern part of the sky at noon during the summer solstice. During the winter solstice, the sun's position in the sky is lower.

Calculating Sun Position at Noon

The exact angle of the sun at noon can be calculated using the solar altitude formula. The formula takes into account the observer’s latitude, the day of the year, and the geographical location. The solar altitude formula is given by:

h 90° - φ δ

h solar altitude at noon (degrees) φ observer’s latitude (degrees) δ declination of the sun (degrees)

Declination (δ) changes with the season, and it ranges from -23.5° (around December 22) to 23.5° (around June 22). The latitude (φ) is a fixed value for each location.

Sun's Position Complement

At noon, the sun appears to be due south in the northern hemisphere and due north in the southern hemisphere, based on your geographical location. However, the accuracy of this position is influenced by factors like the observer's longitude and the Greenwich Hour Angle, making it rarely perfectly south.

Seasonal Considerations

During the winter in the polar regions (above the Arctic or Antarctic circle), the sun can be below the horizon for half the year. This is due to the tilt of the Earth's axis, which limits the perceived height of the sun above the horizon.

Geographical Latitude

The position of the sun at noon varies based on the geographical latitude and the time of the year. In tropical regions, the sun reaches near the zenith (directly overhead) throughout the year, while in polar regions, the sun's maximum height at noon during summer is limited by the Earth's tilt. During the polar winter, the sun can be completely below the horizon.

Conclusion

The sun's location at noon is a dynamic phenomenon influenced by the Earth's position relative to the sun, as well as the observer's geographical location. By understanding the solar altitude formula and the principles behind the sun's position at noon, one can gain a deeper insight into the celestial mechanics that govern our daily experiences.