Monthly Archives: September 2016

Autumnal Equinox

20160922_072958-1

First light, autumnal equinox.

Summer Solstice is the longest day of the year, winter solstice is the shortest. Halfway between the solstices lie the vernal (Spring) and Autumnal Equinoxes. Theoretically, there are equal hours of day and night during an equinox but actually they can vary slightly with a maximum of about seven minutes. Also note that the official demarcation is on the equator, so if you are above or below that line the window of time can widen.

You would think that winter solstice would imply both the latest sunrise and earliest sunset, but actually the latest sunrise takes place in January and the earliest sunset occurs around the first week of December yet solstice generally occurs on December 21 (yep, that day can vary too.)

20160922_183435

Last light, autumnal equinox.

Regardless of assumptions, being close to the longest or shortest days (solstices), or halfway between those days (equinoxes) are noteworthy regardless of what hemisphere you live in and all have been celebrated since since humans started observing the pattern.  It is fun to stop at least four times a year and appreciate the basis for our calendar.  Take a note tomorrow of the point on the horizon where either the sun rises or sets. Return to that same spot around December 21, and you will be surprised how far along the horizon those events appear move.

20160922_074348

Daybreak on Black Mountain, autumnal equinox.