Archive
10/03/11 – Ephemeris – More celestial events for this month
Monday, October 3rd. The sun will rise at 7:42. It’ll be up for 11 hours and 37 minutes, setting at 7:19. The moon, at first quarter today, will set at 12:10 tomorrow morning.
We have more celestial happenings this month than I could enumerate last Friday. Later on Saturday evening, if it’s clear the Grand Traverse Astronomical Society will join with astronomy groups, planetariums and observatories with International Observe the Moon Night with telescopes positioned on the 200 block east Front Street in Traverse City, near the Martinek clock. Going on that same evening will be the return of the Draconid meteor shower. Its a favorable return of a periodic shower but interferes with by the bright moon. However some bright meteors will be seen. I’ll have more information and background Thursday. Another meteor shower later this month will be the Orionids a morning shower related to Halley’s Comet.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
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.
09/12/11 – Ephemeris – Harvest Moon tonight
Monday, September 12th. The sun will rise at 7:17. It’ll be up for 12 hours and 41 minutes, setting at 7:59. The moon, at full today, will rise at 7:43 this evening.
Today’s full moon is the famous Harvest Moon, the nearest full moon to the autumnal equinox. This is a time of the full and waning gibbous moons in the next few days rising in twilight. In the old days before electric lights it helped farmers by effectively lengthening the hours of light to gather in the crops. The moon on average rises 50 minutes later each night. The interval between tonight’s moonrise and tomorrow’s will be 22 minutes. The interval between Tuesday and Wednesday will be 24 minutes, between Wednesday and Thursday, 27 minutes. The instant of full moon today is actually past, at 5:26 this morning. The fact that the rising moon appears orange has nothing to do with the Harvest Moon. Like the sun, it’s always orange or red near the horizon.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/08/11 – Ephemeris – The moon tonight
Thursday, September 8th. The sun will rise at 7:12. It’ll be up for 12 hours and 53 minutes, setting at 8:06. The moon, half way from first quarter to full, will set at 4:28 tomorrow morning.
The moon tonight is very bright, so looking at it with a telescope can be almost painful. There are moon filters sold at telescope stores for standard sized eyepieces that will alleviate that problem. Remember it’s daytime on the moon and the sunlight is as strong on the moon as it is on the earth. Concentrate the telescope on the left edge of the moon, the sunrise line where the shadows are. The bright crater Aristarchus is just coming into sunlight now on the upper left. It’s the brightest spot on the moon when the moon is full. The Crater Gassendi to the lower left is a ringed plain with low walls and a flat floor that has a rille or crack in it. Another distinctive crater is Schiller lower to the south and distinctively elongated.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon with craters Aristarchus, Gassendi and Schiller. Image from Virtual Moon Atlas.
Closeup of the crater Gassendi
The crater Gassendi from Apollo 16 - NASA
08/15/11 – Ephemeris – Preview of next month’s harvest moon
Monday, August 15th. The sun rises at 6:44. It’ll be up for 14 hours and 3 minutes, setting at 8:48. The moon, 2 days past full, will rise at 9:16 this evening.
Last Saturday night under partly cloudy skies at the Port Oneida Fair Star Party we saw the full moon rise and it reminded me that the next full moon will be the Harvest Moon. The next few nights will preview the coming harvest moon effect. That is that the moon will rise at nearly the same time for several nights in a row. On average the moon will rise or set 50 minutes later each night. Due to the geometry of the situation the harvest moon for several nights will only rise later by down to 20 minutes a night. Back before electric lights the bright moonlight augmented twilight to increase the daily time available to harvest the crops. This slowdown in the moon’s rise times is affecting us now, though the moon is definitely waning.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/09/11 – Ephemeris – The moon tonight – musings
Tuesday, August 9th. The sun rises at 6:37. It’ll be up for 14 hours and 19 minutes, setting at 8:57. The moon, 3 days past first quarter, will set at 3:19 tomorrow morning.
The moon tonight is in its gibbous phase, as it has been since first quarter last weekend. This Saturday it will be full. So now most of the moon’s face is in sunlight. Besides the dark, lava filled dry seas of the moon, which give us the dark spots that some of us imagine as the face of the man in the moon, we can spot many craters and other formations in a telescope. Even as the moon has been accumulating spacecraft, rocket parts, rovers and Hasselblad cameras for the last 50 years none can be seen from the earth. The Lunar Reconnaissance Orbiter is taking photographs of the moon in unprecedented detail. They’ve already located the Apollo landing sites, and discovered a lost Soviet lunar rover. Who knows what else they’ll find.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/08/11 – Ephemeris – The lunar seas and the possible second moon theory
Monday, August 8th. The sun rises at 6:36. It’ll be up for 14 hours and 22 minutes, setting at 8:58. The moon, 2 days past first quarter, will set at 2:17 tomorrow morning.
With the announcement last week that the earth may have had two moons, we’d kind of look at our surviving moon in a new light. Tonight the terminator, the line between light and dark on the moon, really the sunrise line crosses through the Sea of Clouds or Mare Imbrium. Telescope will reveal the crater Copernicus near the moon’s equator that will come into sunlight an hour from now as you listen to this. Two astronomers from the US and Switzerland propose that the collision of the earth that created the moon also created another moon. After a time this second, smaller moon crashed into our moon and created the dark seas on the side that faces the earth. The far side of the moon only has one small sea, the Sea of Moscow, discovered by the Russians in 1959 with their Lunik 3 spacecraft.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
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
07/11/11 – Ephemeris – The moon’s Oceanus Procellarum
Monday, July 11th. Today the sun will be up for 15 hours and 19 minutes, setting at 9:27. The moon, 3 days past first quarter, will set at 3:25 tomorrow morning. Tomorrow the sun will rise at 6:08.
The moon tonight is a big fat gibbous phase. The terminator, now before full moon is the sunrise line that creates tonight’s phase. It’s crossing the large sea called Oceanus Procellarum or the Ocean of Storms. It is the moon’s largest sea, though really a lava basin. This is easily seen with the unaided eye and binoculars. The moon has never had oceans or seas of water. That impression was in the eyes of early telescopic observers of the moon , who even thought there was life on the moon. Oceanus is huge, by lunar standards, 434 by 303 miles with indistinct walls. Lunar seas are actually huge craters with an age over 3 billion years.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon's Oceanus Procellarum. Image from the Virtual Moon Atlas.
07/07/11 – Ephemeris – Demonstrate for yourself the phases of the moon
Thursday, July 7th. Today the sun will be up for 15 hours and 24 minutes, setting at 9:29. The moon, 1 day before first quarter, will set at 12:43 tomorrow morning. Tomorrow the sun will rise at 6:05.
The moon changes its phase daily as it orbits the earth. Some still think that it has to do with the earth’s shadow. Now that does happen for a few hours during a lunar eclipse at some full moons. However the moon’s phase is simply the moon in sunlight, the same sunlight that falls on the earth. The dark part of the moon is simply the night side of the moon. It changes because the moon orbits the earth and the farther it appears from the sun, the fuller it appears. This can be proven with a small ball. When the moon’s out in the day time, like it is now before sunset, go out in the sunshine and hold or toss the ball up in the direction of the moon. The ball will have the same phase as the moon.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 