Home >> Science & Nature >> Astronomy

How to Determine a Vernal Equinox

In a year, the earth completes one orbit around the sun. Equinox is the two times of the year when the sun crosses the plane of the earth's equator and when the length of day and night is just about equal in all parts of the world. There are two types of equinoxes that occur each year: the vernal equinox and the autumnal equinox. The vernal equinox occurs during spring, and is believed by many cultures and religions to be the time of rebirth. One of the most popular festivals associated with this is the Easter holiday.

Instructions

- 1
  Check the calendar. The vernal equinox usually occurs around March 20 or 21. The date of the vernal equinox is never exact and tends to move earlier on each occurrence. Since the 1960s, the vernal equinox has been slowly getting earlier.
- 2
  Calculate the vernal equinox with a universal time like GMT (Greenwich Mean Time). Vernal-equinox software is available to determine the point within an hour at which the vernal equinox begins each year. This is done by using complex formulas relating to the stars and sun.
- 3
  Observe the vernal equinox graph to know the positions of earth and be able to compare them to the sun. This is a graph made by experts to help determine when the vernal equinox occurs.

Astronomy