"Jeddah Astronomy" Announces the Date of the Spring Equinox

The spring equinox represents a point of Earth's orbit around the sun and also constitutes a sign of the moment when the sun "apparently" crosses the celestial equator, moving from the south half to the half north of the celestial dome.

On that day, the sun is vertical at the equator and the heat and light are evenly distributed over the hemispheres, while the regions north and south of the equatorial region receive an inclined sun that goes from 90 degrees to zero at the poles due to an inclination of 23.5 degrees from the Earth's axis.

The sun is a circular disk, not a luminous point, like distant stars, as it appears in the sky of the Earth. Most calendars connect the sunrise at the first touch of its edge to the eastern horizon and determine the sunset. When you touch the edge of the western horizon disk of the sun, the sun gives about 3 additional minutes of daylight at mid-latitudes.

The second is the refraction of the air, where the Earth's atmosphere, such as a lens or leaf, raises the sun by 0.5 degrees from its actual geometric position while the sun is approaching the horizon. Luckily, its angular diameter is about 0.5 degrees, which means we see the sun at the horizon. Are actually below the horizon, this leads to the progression of the sunrise and delays its sunset and adds about 6 minutes of daylight to mid-latitudes, so more daylight in moderation.

Astronomical calendars do not usually give rise to sunrise or sunset, and this atmospheric refraction is somewhat variable, depending on low temperature, high humidity, and barometric pressure, all of which increase refraction. atmospheric.

"On the day of the spring equinox, the observer will observe that the sun rises from the point east to the east and back to the original western point. was rising and the sun was getting more and more late, and that he observed every day the path of the sun visible in the sky,.

After weeks of the spring equinox, it will be noted that the sun rises from the northeast, as the earth has changed position around the sun, making the sunrise and sunset points heading north in the sky.

The spring season will last 3 months, 17 hours and 56 minutes until the summer solstice on June 21st.