09/23/11 – Ephemeris – Autumn is already here
Friday, September 23rd. The sun will rise at 7:30. It’ll be up for 12 hours and 8 minutes, setting at 7:38. The moon, 3 days past last quarter, will rise at 4:00 tomorrow morning.
Autumn has arrived. It snuck in at 5:05 a.m. At that instant the sun passed over the celestial equator, earth’s equator projected on the sky, heading southward. By Monday the sun will be up less than 12 hours a day, heading to less than 9 hours at the start of winter, three month’s away. It is the tilt of the earth’s axis, which is fixed as the earth orbits the sun that causes the sun to appear to change its height in the sky at noon and the length of daylight that warms the earth. Its is not the small change in the distance of the earth from the sun. And besides the earth is currently moving closer to the sun and will arrive at its closest, called perihelion in early January.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 