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

April 7, 2020 Leave a comment

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 Leave a comment

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

12/05/2019 – Ephemeris – Artemis the new Moon program

December 5, 2019 Comments off

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.

Orion MPC

Cone-shaped Orion Multi-Purpose Crew Vehicle with a European Service Module. Credit NASA.

Lunar Gateway

Lunar Gateway supplied by the same partners that built the International Space Station. It will orbit the Moon, Credit NASA.

Lunar Lander

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

December 3, 2019 Comments off

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

Binocular Moon

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.

Scallop shell

Image of a scallop shell rotated to match the Sea of Serenity. Credit Wikipedia user Kevmin. (Creative Commons)