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09/20/2013 – Ephemeris – The September equinox and astronomy at Fishtown
Ephemeris for Friday, September 20th. The sun will rise at 7:27. It’ll be up for 12 hours and 15 minutes, setting at 7:43. The moon, 1 day past full, will rise at 8:11 this evening.
At 4:44 in the afternoon Sunday autumn will begin. More important and sad for me is that summer will also end. Since March 20th the sun has been north of the celestial equator, shining directly over some part of the northern hemisphere tropics, but Sunday it moves south of the equator, causing sunset at the north pole and sunrise at the south pole. That point in time is called the autumnal or September equinox. In a few days daylight hours here will drop below 12 hours and keep on dropping until we near Christmas. On a brighter note: During the day Saturday, that’s tomorrow, the Grand Traverse Astronomical Society will have their telescopes down at Fishtown for the Leland Heritage Celebration, that’s 10 am to 5 p.m. in Leland Michigan.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Earth looking from the direction of the sun at the moment of the Autumnal Equinox, 4:44 p.m.EDT September 22, 2013. Created using Celestia.
GTAS at Fishtown in 2011.
03/19/2013 – Ephemeris – PanSTARRS, of course, plus a spring preview
Ephemeris for Tuesday, March 19th. The sun will rise at 7:47. It’ll be up for 12 hours and 6 minutes, setting at 7:53. The moon, at first quarter today, will set at 3:38 tomorrow morning.
Comet PanSTARRS continues to be seen low in evening twilight. It is moving now into the west northwest. When it becomes dark enough it will display a fan shaped tail in binoculars. It is moving away from both the sun and the earth. Tomorrow will see our own milestone as the earth moves into a position where the sun appears over the earth’s equator, and the sun sets at the south pole of the earth and rises at the north pole. It will be the vernal or spring equinox. Australians and other folks south of the equator may prefer to call it the March equinox, because for them autumn starts. The exact time the sun will appear to cross the equator heading northward will be 7:02 tomorrow morning. The sun will keep heading northward until June 21st.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet PanSTARRS for this week’s weekdays at 9:15 p.m. Created using Stellarium and Cartes du Ciel.
The earth as seen from the sun near the vernal equinox. See the earth from north pole to south pole. Created using Celestia.
Bob Moler's Ephemeris Blog 