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09/03/2020 – Ephemeris – Why is the new NASA Moon landing program called Artemis?

September 3, 2020 Comments off

This is Ephemeris for Thursday, September 3rd. Today the Sun will be up for 13 hours and 6 minutes, setting at 8:14, and it will rise tomorrow at 7:09. The Moon, 1 day past full, will rise at 9:20 this evening.

Why is the new NASA crewed Moon landing program called Artemis? And why is it crewed, and not manned? Artemis was a Greek deity and Apollo’s twin sister. He was the god of the Sun and she was goddess, among other things, of the Moon. So she has a greater connection to the Moon than Apollo did. Spacecraft now-a-days are crewed, rather than manned to denote that both sexes are chosen to be astronauts in nearly equal numbers now. Of course that’s crewed spelled c-r-e-w-e-d, not c-r-u-d-e, though they sound the same. Deities of the Moon tend to be female be they Artemis, Cynthia, Luna, Selene, or Chang’e. Astronomers use Cynthia, Luna, and Selene (pronounced Sel-e-nae) in naming various aspects of the Moon and Chang’e is the goddess that the Chinese name their lunar landers after.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

NASA Artemis Logo

The logo chosen by NASA for the Artemis Program. The blue crescent at the bottom represents the earth. The gray ball at the top is the Moon. The curved red path is the stylized return path from the Moon to the Earth of the Orion capsule. Credit: NASA.

Artemis, goddess of the hunt and the Moon.

Artemis, goddess of the hunt and the Moon. Credit: Disney (Fantasia) source Daily Kos.

 

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08/28/2020 – Ephemeris – Tonight Jupiter and the Moon will appear together in the sky

August 28, 2020 Comments off

This is Ephemeris for Friday, August 28th. Today the Sun will be up for 13 hours and 24 minutes, setting at 8:25, and it will rise tomorrow at 7:02. The Moon, 3 days past first quarter, will set at 2:56 tomorrow morning.

Tonight at 9:33 pm the Moon will pass Jupiter in our skies. Jupiter will appear about 5 moon-widths above the Moon. It’s a good time to get out those binoculars or a small telescope to look at them. Jupiter will have its four brightest moons, two on each side. They are pretty close in. Tomorrow night they will all be on the west side of the planet. The waxing Gibbous Moon shows most of the Earth facing side now. The sunrise line a day ago brought the crater Copernicus into light on the east or left side of the Moon. Otherwise the east side of the Moon is flatter than the west side being dominated by two flat lunar seas, actually lava plains called the Sea of Clouds and Ocean of Storms. The Moon has never seen clouds or storms.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Jupiter, Saturn and the Moon

Jupiter, Saturn and the Moon as they would appear to the naked eye at 9:33 pm tonight August, 28, 2020. Created using Stellarium which unfortunately shows the Moon dimmer than the planets. In reality is that the Moon very much brighter, almost overpowering the planets.

Telesscopic Jupiter

Jupiter and its 4 Galilean moons as the would appear in a telescope tonight August 28, 2020. Created using Cartes du Ciel (Sky Chart).

Gibbous Moon

The gibbous Moon tonight as it might appear in a low power telescope. Created using Stellarium.

 

06/08/2020 – Ephemeris – Tomorrow’s Moon and the morning planets

June 8, 2020 Comments off

This is Ephemeris for Monday, June 8th. Today the Sun will be up for 15 hours and 29 minutes, setting at 9:26, and it will rise tomorrow at 5:57. The Moon, 3 days past full, will rise at 12:28 tomorrow morning.

This afternoon the Moon will pass south of Jupiter, and this evening it will pass south of Saturn. By tomorrow morning the Moon will be to the lower left of both of them. However to see them one should get up by 5 am. By 5:30 the planets will be pretty much lost in twilight. The Moon should still be easily visible low in the south at that time. A careful observer, over time, may notice that both Jupiter and Saturn are moving slowly westward, rather than their normal eastward movement. We call this motion retrograde motion. This motion baffled the ancient Greeks, who thought the Earth to be stationary and the planets moved uniformly in perfect circles. They kind of solved it by adding smaller circles to the original ones.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Moon and morning planets

The Moon and morning planets at 5 a.m. tomorrow morning in the eastern US at 5 am, June 12, 2020. Created using Stellarium.

05/28/2020 – Ephemeris – The Moon tonight and the origin of the lunar seas

May 28, 2020 Comments off

This is Ephemeris for Thursday, May 28th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 1 day before first quarter, will set at 2:25 tomorrow morning.

Tonight’s Moon is a fat crescent. The lower or southern part of the Moon are brighter. These are the lunar highlands, the more rugged crater filled part of the Moon. The darker areas are the so-called lunar seas, huge lava filled craters. Note that they appear to be roughly circular. They are thought to be the result of large asteroid impacts that occurred four billion years ago during what is known as the late heavy bombardment. The late heavy bombardment is still controversial. One theory has that the outer planets changed their orbits in time disrupting the two areas of small bodies, the asteroid belt inside Jupiter’s orbit and the Kuiper belt beyond Neptune, sending some of them into the inner solar system.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Moon at low magnification

The Moon at low magnification this evening, May 28, 2020 with the English names for the visible lunar seas. Created using Stellarium.

04/27/2020 – Ephemeris – Sunrise at Theophilus

April 27, 2020 Comments off

This is Ephemeris for Monday, April 27th. Today the Sun will be up for 14 hours and 5 minutes, setting at 8:43, and it will rise tomorrow at 6:36. The Moon, 3 days before first quarter, will set at 1:26 tomorrow morning.

If my Moon charting software is correct this is the one evening out of the month when the central peak of the crater Theophilus catches the first rays of the rising Sun, while the crater floor is in shadow. It kind of looks like a bulls eye. It can be spotted with binoculars on the inside of the crescent, on the terminator, the sunrise line about half way between the ends of the crescent. Theophilus is 61 miles (101 km) in diameter. A telescope of any size with 30 to 50 power magnification will really bring out the detail. More magnification may be warranted, but if the bigger image becomes fuzzy, back off the power. It may be the diameter of your telescope due to the wave nature of light or the atmosphere you’re looking through that’s causing the problem.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Binocular Moon with Theophilus at Sunrise

The Moon as it should appear at 10 p.m. tonight April 27, 2020 EDT (2:00 UT the 28th UT) with Theophilus on the terminator. Created with Stellarium.

Theophilus at sunrise

Theophilus at sunrise with the Sun illuminating the central peak and the far crater wall. Theophilus’ diameter is 61 miles or 101 kilometers in diameter. The crater walls rise 13 ,3000 feet or 4,400 meters above the crater floor, and the central mountain with four peaks rises 4,600 feet or 1,400 meters above the crater floor. Image and information from Virtual Moon Atlas. This image needs to be rotated clockwise about 45 degrees to match the image above.

04/07/2020 – Ephemeris – Today is the Paschal full moon

April 7, 2020 Comments off

This is Ephemeris for Tuesday, April 7th. Today the Sun will be up for 13 hours and 6 minutes, setting at 8:18, and it will rise tomorrow at 7:09. The Moon, at full today, will rise at 7:55 this evening.

Tonight’s full moon is the Paschal full moon, the first full moon of spring which is tomorrow in the Holy Land, so Passover begins at sunset tomorrow. Easter for western churches falls on the first Sunday after the first full moon of spring, which is this next Sunday the 12th. Orthodox Easter rule adds that it must fall after Passover,a week long observance, which pushes their Easter celebration to a week later, April 19th. Both Christian churches attempt to mimic the Jewish Lunar Calendar by setting Easter by the first full moon of spring using solar based calendars and assuming that spring started on March 21st. This year actual spring started on the 20th in the Holy Land, and 19th here by 10 minutes, in our Gregorian Calendar and 13 days earlier by the old Julian Calendar. This is all very complicated.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

 

04/06/2020 – Ephemeris – Tomorrow’s full moon is special in two ways

April 6, 2020 Comments off

This is Ephemeris for Monday, April 6th. Today the Sun will be up for 13 hours and 3 minutes, setting at 8:17, and it will rise tomorrow at 7:11. The Moon, 1 day before full, will set at 7:21 tomorrow morning.

The Moon will be full tomorrow, and also it will reach perigee, that is, its closest to the Earth of its current orbit, and for 2020. That makes it a super moon. The orbit of the Moon is affected by the Sun, Venus, and Jupiter mostly. So all perigees are not equally close. At perigee tomorrow the Moon will be 221,772 miles (356,907* km). I its most distant point from the Earth of 252,564 miles (406,462* km). We won’t notice it because it will be nearly new at that time. Tomorrow’s full moon will be special in another way, because it it the full moon that announces Easter for both Christian churches, east and west, and Passover for the Jews. I’ll talk more about that tomorrow.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

* According to Astronomical Tables of the Sun, Moon and Planets Third Edition by Jean Meeus.

04/02/2020 – Ephemeris – Let’s look at the Moon tonight

April 2, 2020 Comments off

This is Ephemeris for Thursday, April 2nd. Today the Sun will be up for 12 hours and 51 minutes, setting at 8:12, and it will rise tomorrow at 7:18. The Moon, 1 day past first quarter, will set at 5:09 tomorrow morning.

Tonight’s gibbous Moon is a bright fixture in the evening sky it’s in the constellation of Cancer the crab which its brightness obliterates, between the stars Castor and Pollux of Gemini on the right and Regulus of Leo on the left. The Beehive star cluster in Cancer can be spotted in binoculars to the left of the Moon by about 7 to 8 of its diameters. On the Moon itself are the gray, so-called seas and two spectacular craters near the terminator. The first is near the bottom limb of the Moon, the very large crater Clavius with an interesting arc of small craters of decreasing size within. The other remarkable crater is Copernicus about half way up and left, near the terminator, the Moon’s sunrise line.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Moon and Beehive Star Cluster

The Moon and Beehive Star Cluster at 10 p.m. tonight April 2, 2020. If you are not in the eastern daylight time the Moon will be in a different position if you are in a different time zone.

Telescopic Moon

The Mon as it might appear in a low power telescope tonight at 10 p.m. April 2, 2020. Created using Virtual Moon Atlas (software).

03/30/2020 – Ephemeris – Following the Moon night to night

March 30, 2020 Comments off

Ephemeris for Monday, March 30th. Today the Sun will be up for 12 hours and 42 minutes, setting at 8:08, and it will rise tomorrow at 7:24. The Moon, 2 days before first quarter, will set at 2:32 tomorrow morning.

Now that clear skies are mostly back we can follow, night by night the progress of the Moon, now as its phase waxes and moves eastward at the same time each night. With the naked-eye the large darker lunar seas slowly reveal the face of the Man in the Moon, or the Chinese upside down Jade Rabbit pounding medicine with his mortar and pestle. With binoculars or telescope, more detail is revealed every night as the terminator, the sunrise line before full moon uncovers more lunar territory, with their long morning shadows. It’s the shadows that show the detail on the Moon, which is dark gray on darker gray. For the most part the surface of the Moon has been worn down by eons of meteoroid impacts and their ejecta.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Jade Rabbit on the Moon

Jade Rabbit and Mortar on the Moon. Credit: Zeimusu, Creative Commons.

Cratewrs near the termonator

Craters near the Moon’s terminator showing how the low Sun brings out the detail. Credit Bob Moler, the author on 06/11/2011.

03/02/2020 – Ephemeris – Greek use of the first quarter Moon

March 2, 2020 Comments off

Ephemeris for Monday, March 2nd. Today the Sun will be up for 11 hours and 14 minutes, setting at 6:32, and it will rise tomorrow at 7:15. The Moon, at first quarter today, will set at 2:39 tomorrow morning.

The Moon is at first quarter at 2:57 this afternoon. The ancient Greek philosopher/astronomer Aristarchus* tried to determine the distance to the Sun by observing the Moon at exactly first quarter and measuring the angle between it and the Sun. If we see the Moon at exactly first quarter when the sunrise line called the terminator cuts the Moon exactly in half then the angle at the Moon between the Sun and the Earth is a right or 90 degree angle. If we, on the Earth at that same instant were able to measure the angular distance between the Moon and the Sun. we could theoretically calculate the distance to the Sun. He was correct about the Moon’s distance, but calculated the Sun was at only about 10% of its actual distance.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

* In the actual broadcast program I erroneously credited the later Greek astronomer Hipparchus.

Addendum

Quarter Mon method of determining the Sun's distance

Quarter Moon method of determining the Sun’s distance by Aristarchus. Credit: andonee