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09/15/11 – Ephemeris – The waning gibbous moon tonight
Thursday, September 15th. The sun will rise at 7:21. It’ll be up for 12 hours and 32 minutes, setting at 7:53. The moon, 3 days past full, will rise at 8:56 this evening.
I don’t usually talk about the moon after it becomes full, but because of the harvest moon effect its still rises early. The moon’s phase is now a waning gibbous, with the sunset line now crossing the moon from right to left. Visible are the dark seas including to the upper right the scallop shell shaped Sea of Serenity. In telescopes at its right edge will be the crater Posidonus a flat crater, 58 miles in diameter, with low walls with an inner partial crater ring within. Larger telescopes may be able to see cracks or rilles in its floor. The sea south of Serenity is Tranquility where Apollo 11 landed and by tomorrow night the sun will nearly have set there as well as having encroached on Serenity
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon 9/15/11 10 p.m. Created using Virtual Moon Atlas.
08/04/11 – Ephemeris – The moon’s Sea of Tranquility
Thursday, August 4th. The sun rises at 6:32. It’ll be up for 14 hours and 32 minutes, setting at 9:04. The moon, 2 days before first quarter, will set at 11:18 this evening.
In binoculars the center of the of the moon and clipped by the terminator, the moon’s sunrise line is the landing area of the first humans on the moon The Sea of Tranquility. It is a circular basin 424 miles in diameter with a flat floor. It was formed in the first 600 million years of the moon’s existence after the worst of the cratering was over. The moon appears to have been formed by a glancing collision of a Mars sized body with the earth during the formation of the solar system. The debris circled the earth and condensed to form the moon. It is from studying the rocks brought back by the Apollo astronauts that this origin scenario was first put forth. The origin of a huge satellite for the earth had baffled astronomers before this discovery..
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Sea of Tranquility emerging into sunlight - Virtual Moon Atlas
Bob Moler's Ephemeris Blog 