During April, the days grow significantly longer since the equinox (the first day of spring). The Sun rises earlier and sets later, and is now quite high in the sky at noon. As a result, by month’s end, the length of daylight is almost two hours longer than at the beginning of spring. Note in the figure that, by … Continue reading
Category: Seasonal Sun
Seasonal Twilight
Twilight is the shortest during the spring and fall. In the morning, before sunrise, daylight comes on quickly closest to the equinoxes. In the evening, after sunset, night falls quickly, as the sky fades after sunset. Equinoctial twilights can be 45 minutes in the mid-temperate latitudes of North America. However, summer twilights are the longest of the year! In … Continue reading
The Vernal Equinox
SPRING BEGINS TODAY AT 6:45 PM EDT. This is the precise moment when the Sun is centered on the VERNAL EQUINOX. The vernal equinox is actually a location in the starry sky, the origin of the coordinate system of the celestial sphere. The place of the vernal equinox is where the celestial equator (0 degrees of declination) intersects with … Continue reading
The Vernal Equinox
On the vernal equinox, the Sun rises perfectly due east, and sets 12 hours later, exactly due west. Be sure to notice this if you can see the sunrise or sunset on the day of the equinox, March 20. The Sun is on the celestial equator, the midpoint between the celestial poles, balanced between the northern and southern constellations. … Continue reading
Noon on the Vernal Equinox
The vernal equinox is March 20. Spring begins for the northern hemisphere at the precise moment when the Sun is centered on the celestial equator, zero degrees in declination, the midpoint between the north and south celestial poles. Every location in the world will experience 12 hours of daylight and 12 hours of nighttime…. except the North and South … Continue reading
The Sun in March
During March, as winter draws to a close, the Sun rises to the south of due east and sets to the south of due west. By the end of the month, after spring begins, the Sun rises to the north of due east, at an earlier time than at the beginning of the month. Similarly, the Sun sets to … Continue reading
The Sun During March
Due to the Earth’s annual revolution, the line of sight between the Sun and the background constellations is constantly changing. This appears as the Sun moving east through the constellations of the zodiac. During March, the Sun appears to be moving from the constellation Aquarius to Pisces. In the process, the Sun crosses the celestial equator, an invisible circle … Continue reading
Noon During March
During March, the days grow significantly longer. The Sun rises earlier and sets later, and is now quite high in the sky at noon. As a result, by month’s end, the length of daylight is three hours longer than on the shortest day, back in December. Continue reading
Noon During February
The days have grown noticeably longer through February. The Sun increases 9 degrees in declination over month, a total of 15 degrees since the winter solstice, and the noon Sun is higher in the sky by that amount. As a result, by month’s end, the length of daylight is two hours longer than on the shortest day, with sunrise … Continue reading
Noon During January
The days begin to get longer in January as the Sun increases in declination, rising higher in the noon sky and having a more northerly amplitude at sunrise and sunset. Continue reading
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