Archive
04/02/2020 – Ephemeris – Let’s look at the Moon tonight
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
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.
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
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 and Mortar on the Moon. Credit: Zeimusu, Creative Commons.
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
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 Moon method of determining the Sun’s distance by Aristarchus. Credit: andonee
12/05/2019 – Ephemeris – Artemis the new Moon program
Ephemeris for Thursday, December 5th. Today the Sun will be up for 8 hours and 58 minutes, setting at 5:02, and it will rise tomorrow at 8:05. The Moon, 1 day past first quarter, will set at 2:01 tomorrow morning. | NASA has a new program to return to the Moon, perhaps to stay. The program is called Artemis, named after the Greek god Apollo’s twin sister. NASA is building a massive rocket called the Space Launch System, or SLS, and the Orion
, which I’m sure will guarantee European astronauts a ride. This is not going to be an Apollo type one rocket up and back. There will be a space station called the Lunar Gateway of International partners that will orbit the Moon. There the crew of the Orion Spacecraft will transfer to a Lunar Lander for the trip to and from the surface of the Moon. It’s a heavy push to accomplish by 2024.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Block 1b vrsion of the Space Launch System (SLS) which uses elongated Space Shuttle boosters and a core stage with 4 Space Shuttle main engines for the first stage. Credit NASA.
Cone-shaped Orion Multi-Purpose Crew Vehicle with a European Service Module. Credit NASA.
Lunar Gateway supplied by the same partners that built the International Space Station. It will orbit the Moon, Credit NASA.
Lunar Lander. This vehicle has not been designed yet. This is Blue Origin’s Ascent Module on top of a yet to be designed propulsion module. Credit Blue Origin.
12/03/2019 – Ephemeris – The Moon tonight
Ephemeris for Tuesday, December 3rd. Today the Sun will be up for 9 hours and 1 minute, setting at 5:03, and it will rise tomorrow at 8:02. The Moon, 1 day before first quarter, will set at midnight.
The Moon tonight is a few hours before being at first quarter, when the Moon appears exactly half illuminated. In viewing the Moon with a pair of binoculars or a telescope the observer will notice that the best detail is seen near the terminator, the sunrise line, that’s cutting the Moon in half. That’s where the shadows are longest. The large gray feature at the upper right of the Moon is Mare Serenitatis, which translates to the Sea of Serenity. To me it appears to look like a scallop shell. Serenitatis like most other seas is roughly circular and is actually a crater, the result of an impact of a large asteroid during what is called the late heavy bombardment that happened about 4 billion years ago.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon as will appear tonight at 8 p.m. December 3, 2019 EST. Moon image credit NASA Scientific Visualization Studio.
Images of the moon’s phase for the entire year are available from https://svs.gsfc.nasa.gov/4442.
Image of a scallop shell rotated to match the Sea of Serenity. Credit Wikipedia user Kevmin. (Creative Commons)
11/07/2019 – Ephemeris – The gibbous Moon tonight
Ephemeris for Thursday, November 7th. Today the Sun will be up for 9 hours and 55 minutes, setting at 5:23, and it will rise tomorrow at 7:30. The Moon, 3 days past first quarter, will set at 3:13 tomorrow morning.
Every night when we look at the Moon the sunrise terminator has moved farther west on the Moon which is to our east uncovering more landscape. The Moon rotates once in about 29 ½ days in relation with the Sun. This is the same time it orbits the Earth from new Moon to the next. We call that a lunation or lunar month. Near the upper left corner of the Moon is what looks like a half crater. It’s called Sinus Iridium, the Bay of Rainbows. It’s at the edge of Mare Imbrium or Sea of Showers. To the south cut by the terminator is Oceanus Procellarum, the flat Ocean of Storms. South of that is the small Mare Humorum, the Sea of Vapors. South of all that is the odd shaped crater Schiller.
10-11-2016 has images
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The gibbous Moon tonight at 8 p.m., November 7, 2019. Click on the image to enlarge. Created using Virtual Moon Atlas.
Sinus Iridium photographed by the Lunar Reconnaissance Orbiter as texture mapped on the globe of the Virtual Moon Atlas.
Clavius as photographed by one of the Lunar Orbiter spacecraft in the 1960s From Digital Lunar Orbital Photographic Atlas. This is photographed from overhead. On tonight’s moon it’s near the bottom or south end and is foreshortened.Credit Jeff Gillis, Lunar and Planetary Institute.
10/03/2019 -Ephemeris – The Moon tonight
Ephemeris for Thursday, October 3rd. Today the Sun will be up for 11 hours and 37 minutes, setting at 7:20, and it will rise tomorrow at 7:44. The Moon, 2 days before first quarter, will set at 10:46 this evening.
The planet Jupiter will appear below and right of the crescent Moon tonight. This evening one of the striking lunar craters will be seen at the sunrise line or terminator on the Moon. The crater might just be glimpsed in steadily held or tripod mounted binoculars, and definitely in a small telescope. The crater is Theophilus, some 61 miles (101 km) in diameter located south of the Sea of Tranquility. At lunar sunrise the central peak of the crater catches the Sun of the lunar sunrise way before the floor is illuminated showing a point of light within the circular crater rim against the black floor of the crater. That should happen before the Moon sets at quarter to 11 p.m. The central peak extends 650 feet (200 m) above the crater walls.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Crater Theophilus on the Moon’s terminator at10 p.m. October 3, 2019, Created using Virtual Moon Atlas.
09/13/2019 – Ephemeris – Harvest Moon tonight
Ephemeris for Friday, September 13th. Today the Sun will be up for 12 hours and 38 minutes, setting at 7:57, and it will rise tomorrow at 7:20. The Moon, 1 day before full, will rise tonight 8:12.
Tomorrow is the Harvest Moon. In fact the instant of full moon is 12:33 a.m. tonight, so one could consider the Harvest Moon tonight. Funny thing though, this morning the Moon will reach apogee from the Earth, of 252 thousand miles (406 thousand km), making it the opposite of a super moon, a mini moon. I bet you wouldn’t notice if I didn’t tell you. The Harvest Moon is the name given to the nearest full moon to the autumnal equinox. It is a special time of the lunar cycle when the Moon rises much less than the 50 minutes later average each night. This appeared to extend twilight allowing farmers before the advent of electric lights extra time to gather in their crops each day.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Harvest Moon effect from September 11 to the 15th, 2019. Note the shallowness of the ecliptic and Moon’s motion near sunset in this period. Click on the image to enlarge. Created using Cartes du Ciel (Sky Charts).
09/10/2019 – Ephemeris – India’s second lunar spacecraft
Ephemeris for Tuesday, September 10th. Today the Sun will be up for 12 hours and 47 minutes, setting at 8:03, and it will rise tomorrow at 7:16. The Moon, 4 days before full, will set at 4:29 tomorrow morning.
On July 22nd the Indian Space Research Organization ISRO launched Chandrayaan-2, their second mission to the Moon. India’s Chandrayaan-1 was a lunar orbiter launched 11 years ago. Chandrayaan-2 is much more ambitious spacecraft with an orbiter, a lander with a rover. Last Friday the lander attempted to land within 30 degrees of the Moon’s south pole. Unfortunately contact was lost when the lander was only 2.1 kilometers above the lunar surface. The last data received suggests that the lander’s vertical speed was excessive, and that it likely crashed on the lunar surface. This is the second failed lunar landing attempt this year after the Israeli Beresheet failure in April.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Chanrrayaan’s Vikram lander and Pragyan rover. before launch. The orbiter, not shown, is expected to have a 7 year life. The orbiter has viewed the landing site and has shown that the lander is in one piece. Credit ISRO.
07/16/2019 – Ephemeris – 50 years ago today the Apollo mission left for the Moon
Ephemeris for Tuesday, July 16th. Today the Sun will be up for 15 hours and 12 minutes, setting at 9:25, and it will rise tomorrow at 6:13. The Moon, at full today, will rise at 9:30 this evening.
50 years ago today at 11:32 a.m. Eastern Daylight Time the most powerful rocket ever built roared into life. The Saturn V, a three stage rocket, 363 feet tall, which in turn launched two spacecraft, the Command and Service modules, and the Lunar Module, and three astronauts on their journey to destiny, Neil Armstrong, Edwin (Buzz) Aldrin, and Michael Collins. It was the start of the Apollo 11 mission. It happens that tonight the namesake of the rocket, the planet Saturn is to the right of the Moon. At launch the Moon was two days old, a thin crescent in the west that evening. Four days later they would be orbiting the Moon, and Armstrong and Aldrin would be descending to the Moon’s surface.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
Apollo 11
Left to right Neil Armstrong, Mission Commander; Michael Collins, Command Module Pilot; and Buzz Aldrin, Lunar Module Pilot. Credit: NASA.
The Saturn V for the Apollo 11 mission lifts of from Pad 39A. Credit: NASA.
The Moon and Saturn tonight, 11 p.m. July 16, 2019. In reality the Moon will be so bright that Saturn will be almost overwhelmed. Created using Stellarium.
Here’s an excellent podcast series from the BBC: 13 Minutes to the Moon.
Partial Lunar Eclipse
The partial lunar eclipse today is not mentioned in the program because it is not visible locally.
Partial Lunar Eclipse of July 16, 2019. Click on image to enlarge. Credit NASA/GSFC/F. Espenak.
Bob Moler's Ephemeris Blog 