Noon Sun During May

  During May, the days grow long much less than in April, since the Sun increases only 7 degrees in declination, compared to 14-1/2 degrees in that previous month. (Compare with the previous month’s graphics.) The length of daylight only increases between 23 to 54 minutes for most locations in the USA, whereas daylight increased nearly two hours in April.… Continue reading

The Sun in Aries During April

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 April, the Sun appears to be moving from the constellation Pisces into Aries. In the process, the Sun appears to be moving north from the celestial… Continue reading

  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

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

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

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