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(As of 8/24/09 )

Listen to Aileen on NCPR
Sky & Telescope Magazine's Sky At A Glance
Space.com's Sky Calendar
Sky News Magazine Royal Astronomical Society of Canada
Mountain Skies articles from Adirondac Magazine
"Keep Us in the Dark" published in Adirondack Explorer


Autumnal Equinox 2009
Tuesday, September 22, 5:22 pm EDT


Sun crosses the equator into the northern hemisphere. It is in the constellation of Pisces.
Position of Sunrise & Sunset
The position of sunrise and sunset change through the year, moving north from the winter solstice to the summer solstice and south from the summer to the winter solstices. In Canton, the total solar motion is 68° as shown below for the sunrise. The solstice is the "pause" of the sun as it reaches its northernmost or southernmost point, stops, and stars moving in the opposite direction.
The sun moves fastest at the equinixes when the position of sunrise or sunset changes as much as the width of the full moon (1/2°) each day. During the 20 days surrounding the solstices, the position shifts by less than 1/10°, hence the sun seems to pause.
The graph to the right shows the aziumuth of rising for the sun through the year in Canton. Click for a larger image.
Hours of Daylight
The length of the day changes with the position of the sun as shown on the following graphs for Canton, NY (click for larger versions).

At the solstices, the number of hours of daylight are maximum or minimum and change very little. At the equinoxes there are 12 hours of daylight and the length of the day is changing most rapidly, gaining or losing more than 3 minutes of daylight each day.