I enjoy keeping track of the orbital events of our home planet. Each of the markers of the year’s four quarters have kept me fascinated for as long as I can remember. Perhaps it’s because of my Scandanavian heritage? In the far north, the passing of each season has been held with more notice and reverence, because of the weather’s impact on life in that area of the earth.
The tilt of the earth’s axis in relation to the imaginary plane of orbit is the major factor in determining our climate and weather conditions in various parts of the globe. So, when the sun appears to be at it’s furthest North or South, we have our solstices. When the sun is exactly between those solstice measurements, we have the equinoxes.
Today is the equinox for Autumn in the Northern Hemisphere. The moment of equinox is 14:49 UTC or 9:49 AM Central Daylight Savings Time where I’m at in eastern Nebraska.
One fact that is usually forgotten, is that equinox is the measurement of night. Equinox does not necessarily mean the day and night are of equal duration. The root words of equinox are aequus for equal and nox for night. Because the astronomical event uses the center of the solar disc as the reference point, there is already light in the morning and still light into the evening at equinox. Hence, the appearance of daytime is slightly longer than the night depending upon your position on earth.
There is a lesser known event known as equilux. Equilux is when sunrise and sunset are precisely twelve hours apart. To determine when your area has equilux, you should consult your area’s meteorological tables. For 2012, in Norfolk, Nebraska, equilux will be on September 26th. On this day the first edge of the sun’s disc appearing in the east and the last moment of seeing the departing edge of the sun in the west will be exactly twelve hours apart. Depending on your location on earth and what your area’s geographical features include (mountains, hills or only ocean) will affect the official equilux.
Equinox is the same all over the planet because it is an astronomical event. Again, in 2012, equinox is at 14:49 Universal Time Coordinated or Greenwich Mean Time. Calculate your local time according to the accepted method for your area.
Happy Autumn for folks in the Northern Hemisphere and Happy Spring for residents of the Southern Hemisphere.
The Blue Jay of Happiness is anticipating the annual harvest festivals again.