Tuesday first full day of the Autumnal Equinox 2014

Date: 
09/23/2014
Equinox

Shows the Sun's motion*

Here in the northern hemisphere, the equinox arrived at 9:29 p.m., Sept. 22, and is known as the autumnal equinox. In the southern hemisphere, it's known as the spring equinox.

The event occurs as the sun crosses the celestial equator, making the day and night each 12 hours long. In reality, however, "atmospheric refraction raises the sun's disc by more than its own apparent diameter while it is rising or setting. Thus, when the sun looks like a reddish-orange ball just sitting on the horizon, it's really an optical illusion. It is actually completely below the horizon," according to Space.com

"In addition to refraction hastening sunrise and delaying sunset, there is another factor that makes daylight longer than night at an equinox: Sunrise and sunset are defined as the times when the first or last speck of the sun's upper or lower limbs — not the center of the disc — are visible above the horizon."

Customs, cultural events and religious observances occur around the September equinox and Farmers' Markets start offering more fall offerings. Squashes are already being offered and soon pumpkins will be coming in, bringing us closer to the popular Halloween.

*Image is from Sky & Telescope

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