These events mark the start of the seasons; the equinoxes occur on or about March 21 and Sep 22, while the solstices occur on or about June 21 and December 21. 25. How is an annular eclipse of the Sun different from a total eclipse? What causes this difference? In both annular and total solar eclipses, the Moon lines up precisely with the Sun, center on center. The difference is that in an annular eclipse, the Moon fails to cover the Sun completely, leaving a bright ring. This is caused by the Moon being farther away than usual – its orbit isn’t exactly circular – so that its angular size is smaller. Variation in the distance to the Sun also contributes, since Earth’s orbit is likewise not precisely circular. But the variation in Moon angular size is greater. 27. At what phase(s) of the moon does a solar eclipse occur? A lunar
These events mark the start of the seasons; the equinoxes occur on or about March 21 and Sep 22, while the solstices occur on or about June 21 and December 21. 25. How is an annular eclipse of the Sun different from a total eclipse? What causes this difference? In both annular and total solar eclipses, the Moon lines up precisely with the Sun, center on center. The difference is that in an annular eclipse, the Moon fails to cover the Sun completely, leaving a bright ring. This is caused by the Moon being farther away than usual – its orbit isn’t exactly circular – so that its angular size is smaller. Variation in the distance to the Sun also contributes, since Earth’s orbit is likewise not precisely circular. But the variation in Moon angular size is greater. 27. At what phase(s) of the moon does a solar eclipse occur? A lunar