12/20/2022 – Ephemeris – Hunting for the Star of Bethlehem: When did Herod the Great Die – Part 1

This is Ephemeris for Tuesday, December 20th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:04, and it will rise tomorrow at 8:16. The Moon, 3 days before new, will rise at 6:20 tomorrow morning.

In looking for the year Jesus was born and the appearance of the Star of Bethlehem, we look to the latter years of Herod the Great’s reign. Jewish historian Josephus recounts that Herod died shortly after an eclipse of the Moon occurred. The date of that eclipse, according to many historians, was March 13th, of 4 BCE and before Passover, a month later. The Greek text of Matthew states that Herod’s visitors, looking for the newborn King of the Jews, were Magi. Magi were priest-astrologers of the Zoroastrian Religion of Persia. That being the case, the Star could have been the triple conjunction of Jupiter and Saturn against the constellation of Pisces, when three times Jupiter passed Saturn between the end of May and early December of 7 BCE.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.

Addendum

The Jupiter-Saturn triple conjunction of 7 BC. Click on the image to enlarge and animate. This animation is at 5-day intervals. The conjunctions took place against the stars of Pisces the fish, a constellation thought, in those days, to be associated with the Jews. The Moon will be popping in and out of the view. It ends in February of 6 BC, when Mars and the Moon enters the picture. Click on the image to enlarge it. Created using Cartes du Ciel and GIMP.

Above is an animation of the triple conjunction of Jupiter and Saturn of 7 BCE in 5 day steps. The body popping in and frame is the Moon. The first conjunction was on May 29th. Both planets stopped their eastward motion around July 6th. Astrologically, they became stationary and began their westward or retrograde motion. The second conjunction was on October 11th. Both planets stopped their westward or retrograde motion on November 1st. Again they were stationary to resume their normal eastward motion. The third and last conjunction was on December 8th. Two months later, on February 21st, of 6 BCE, Mars joined the group as they all move off to the western sky in the evening. Using this triple conjunction as the Star of Bethlehem, Jesus would have been born in the late autumn of 7 BCE or early winter of 6 BCE.

This lunar eclipse candidate for the eclipse that heralded the death of Herod the Great, and the favorite, since the time of Johannes Kepler, is the lunar eclipse of March 13, 4 BCE. It was a partial eclipse, only visible in the predawn hours. This eclipse occurred one lunar month before Passover.
Too little time for all the events Josephus describes. A better lunar eclipse occurred a bit less than three years later. Those defending the 4 BCE eclipse sometimes suggest that the Passover mentioned by Josephus was the next year’s Passover of 3 BCE. If it was the next year’s Passover, why mention Passover at all?

Tomorrow I’ll take a break to look to the naked eye planets, and to the winter solstice. Winter begins tomorrow! Thursday I’ll look to a better lunar eclipse and begin to explore another Bethlehem Star candidate.

07/28/2022 – Ephemeris – Why don’t we have solar eclipses every new moon?

This is Bob Moler with Ephemeris for Thursday, July 28th. Today the Sun will be up for 14 hours and 48 minutes, setting at 9:13, and it will rise tomorrow at 6:25. The Moon is new today, and won’t be visible.

The actual time when the moon is New will be 1:55 pm. The Moon will not eclipse the Sun this time. Why? Because the Moon is nearly 5 degrees, or 10 moon-diameters, north of the Sun. If the Moon orbited the Earth nearly in the same plane that the Earth orbited the Sun, we could have solar eclipses for somewhere on the Earth every new moon. As it is, the Moon orbits the Earth with about a 5-degree tilt to the Earth’s orbit of the Sun. So we get eclipse opportunities of eclipses about one in six new moons for solar eclipse and about the same for full moons and lunar eclipses. Of course, one has to be at the proper location to see them. If the Moon orbited the Earth over the Earth’s equator, like many other moons of other planets, eclipses would be much more rare and only occur around the equinoxes.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

The Sun and Moon at New Moon at 1:55 pm today, seen as if the Earth had no atmosphere and one could see the Sun and stars at the same time. The orange line is the path of the Sun in the sky, called the ecliptic. The red line is the orbit of the Moon. Created using Stellarium.

Earth centered (geocentric) diagram of the heavens called the celestial sphere, showing the apparent orbits of the Sun and Moon. The Moon’s orbit has about a 5-degree tilt (exaggerated here) to the Sun’s apparent orbit, which we call the ecliptic. Solar eclipses occur when the new moon and Sun are near a node. Lunar eclipses occur when the full moon and Sun are near opposite nodes. My diagram.

The orbit of the Moon precesses, so the line of the nodes regresses, that is slowly rotating clockwise, backwards to the motion of the Sun and Moon (and all the rest of the planets), one rotation in 18.6 years.

09/13/2021 – Ephemeris – The Greeks knew the size and shape of the Earth and estimated the distance to the Moon a long time ago

This is Bob Moler with Ephemeris for Monday, September 13th. Today the Sun will be up for 12 hours and 37 minutes, setting at 7:56, and it will rise tomorrow at 7:20. The Moon, at first quarter today, will set at 11:57 this evening.

The Ancient Greeks used lunar eclipses to determine that Earth is a sphere, and worked on determining the distance to the Moon. From ancient times, the Greeks knew that an eclipse of the Moon was caused by the Earth’s shadow falling on the Moon. Since the Earth’s shadow was always circular, no matter where the Moon was in the sky during an eclipse, the Earth must be a sphere since that’s the only three-dimensional body that always casts a circular shadow. They also used the size of the Earth’s shadow to estimate the distance to the Moon. The lunar distance, on average, is 60.8 times the Earth’s radius away. The first estimates were about one third of that. Hipparchus in the 2nd century BC got much closer. It got even better from there.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Partial Lunar Eclipse showing circular arc of the Earth’s shadow. Taken 04:15 UT August 17, 1970. Credit: the author.

The size of the Earth was unknown until Eratosthenes did in 240 BC. He came up with the circumference of the Earth to a fairly high degree. The Circumference is equal to the radius of a sphere or circle by 2πr.

12/20/2019 – Ephemeris – The Star of Bethlehem, the problem of when

Ephemeris for Thursday, December 20th. The Sun will rise at 8:16. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The Moon, 2 days before full, will set at 6:46 tomorrow morning.

In looking at the possible origin of the Star of Bethlehem, the latest Jesus could have been born is before the death of Herod the Great. The Jewish historian Josephus says that Herod died between a lunar eclipse and Passover, with most Star investigators pointing to the partial eclipse of March 13, 4 BC, one month before Passover that year. Problem is that Josephus devotes 4 chapters of the 17th book of Jewish Antiquities to the events in that span. I think they chose that eclipse to fit in with the triple conjunction of Jupiter and Saturn in 7 BC that was the big favorite for the star. There is another, better total lunar eclipse on January 10, 1 BC that is 3 months before Passover that would better fit Josephus’ narrative and a different Star possibility. More Monday.

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

Addendum

The passage about Herod’s death from the eclipse of the Moon to Passover is in Josephus’ Antiquities of the Jews is in Book 17, Chapter 6, Paragraph 4 through Chapter 9, paragraph 3.

In doing some additional research since recording the program, the footnotes in William Whiston’s translation suggests a period between the eclipse and Passover at 13 months.  Antiquities of the Jews can be found here: https://www.gutenberg.org/files/2848/2848-h/2848-h.htm.  Of course I could extend the time frame of Herod’s death for the 1 BC eclipse to the Passover 16 months later.  That would solve one of the problems I had with the timing of the visit of the Magi.  But you’ll have to wait until Monday to find out what that is.

Ephemeris for the real Columbus Day for once, Monday, October 12th.  The Sun will rise at 7:54.  It’ll be up for 11 hours and 9 minutes, setting at 7:03.  The Moon is new today, and won’t be visible.

On Columbus’ 4th voyage to the Caribbean he was stranded on Jamaica.  For a while the natives of the island fed Columbus and his men.  However due to the thievery of some of his crew, these people no longer trusted Columbus any refused them any more supplies.  Columbus consulted a table of eclipses and found that a lunar eclipse was to occur on February 29th that year (1504), and that at his location the moon would rise in eclipse.  He went to the leader of the people and said that they had displeased their god by refusing his crew food, and that the god would turn the Moon red in anger.  It worked.  As Arthur C. Clarke once wrote: “Any sufficiently advanced technology is indistinguishable from magic.”

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

Addendum

The moon rising from Jamaica February 29, 1504 as shown by Stellarium with some additional shadow darkening by myself.

Tomorrow I’ll look at what Columbus got wrong… Beside being lost.

I note for the record that Stellarium calendar dating includes what I call the Gregorian discontinuity.  It drops the 10 days between October 4, 1582 and October 15th, which was the adjustment the Gregorian calendar makes to move ahead the actual vernal equinox from March 11 to the 21st.  Christian churches always  use the tabular value of March 21 as the vernal equinox for the calculation of the date of Easter.  The old Julian calendar let that slip back about 3/4 of a day every century.

My 9/27/2015 lunar eclipse experience

This is an elaboration of an email sent to a fellow amateur astronomer who was completely clouded out and asked how we did.

The Grand Traverse Astronomical Society decided to split our forces for the eclipse.  Some of us would be stationed at the Rogers Observatory, south of Traverse City; while the other would participate in an eclipse watch at the Sleeping Bear Dunes National Lakeshore about 30 miles to the northwest of Traverse City. For most of the week before, the weather forecast was for clear weather.  Well, it was not to be.  All day we were under low clouds streaming up from the southwest.

I headed the contingent that would join a park ranger at the spot in the park called the Dune Climb.  There was a mix-up in the location of the watch.  I had it at a location 20 miles to the south.  So I went to that location and posted a sign about the change in venue and headed north to the Dune Climb.  On my way, I ran into some misty rain.  Not exactly encouraging.  On the satellite images I was tracking all day Sunday, the western edge of this big cloud system was over Lake Michigan.  I was hoping a weather system approaching from the northwest would push this cloud system out of the way.  It didn’t quite.

At the Dune Climb, we had reports from one of the visitors that they had seen the Moon from the town of Empire, about 5 miles south of there.  That was before the eclipse started.  At about 9:15 the park ranger Peggy welcomed everyone and soon turned the mic over to me.  Two other members of the GTAS had arrived before me:  Don Flegel and Emmett Holmes.  Don would use the park’s 4-inch refractor.  Emmett brought his wonderful wooden 13 inch telescope on a Dobsonian mount on a Poncet platform.  Both telescopes would be deployed if the skies cleared.  I brought my telescope, but it turned out that I was spending too much time yakking to actually set it up.  With no Moon visible, I ended up talking all about lunar eclipses, and what to expect if the Moon ever popped out of the clouds.  I talked about lunar eclipses, then turned to the solar eclipses I’ve seen and other topics in response to questions, for about an hour and a half.  At about 10:30 we noticed we could see stars to the low southwest over the dunes.  It took 15 minutes, but the hole in the clouds expanded and finally uncovered the Moon at about the mid-eclipse point.

From mid-eclipse, about 10:45, to the end of totality it was almost perfectly clear,  We had light clouds after that to the end of the partial phase.  Then it clouded up again.  My impressions of the eclipse brightness at totality was that it was a bit darker than usual, but I may be wrong.  However, I have had wretched luck in being able to view lunar eclipses.  We were virtually wiped out by clouds with the two lunar eclipses last year, and we’ve had the same luck for the many eclipses occurring before.  I may be out of practice.

The folks stationed at the Rogers observatory were indeed clouded out.  To paraphrase the crusader in Indiana Jones and the Last Crusade:  “We chose wisely.”  Or it was plain dumb luck.

From the animation of the satellite images from Sunday night. The red circle points to the hole, really a notch in the clouds that allowed us to see the last part of the lunar eclipse.  Our low clouds were warm in the infrared, so show as a very light gray. Credit NOAA/Environment Canada.

How to view tonight’s lunar eclipse if you are clouded out or on the wrong side of the planet

There will be a live webcast of the lunar eclipse from the Coca Cola Space Science Center in Columbus, Georgia if they’re not cloudy.  Go here.

Tip of the old observer’s cap to spaceweather.com.   If you haven’t yet subscribe to their free email notification service.

The partial phase of the eclipse starts at 9:07 p.m. EDT.  Totality lasts from 10:11 p.m. to 11:23 p.m. when the ending partial phase commences.  The partial phase will end at 12:27 a.m.

 

 

 

09/25/2015 – Ephemeris – There will be a great lunar eclipse Sunday night

Ephemeris for Friday, September 25th.  The Sun will rise at 7:33.  It’ll be up for 12 hours and 1 minute, setting at 7:35.   The Moon, 2 days before full, will set at 5:34 tomorrow morning.

Lets check out Sunday’s total lunar eclipse.  It will be visible from the entire contiguous 48 states, and in its entirety from Colorado, eastward.  The partial phase will start at 9:07 p.m.  Totality will begin at 10:11 p.m. and extend to 11:23 p.m. when the Moon should appear red in color, illuminated by the combined sunrises and sunsets occurring on the Earth at that moment.  The eclipse will end at 12:27 a.m.  The eclipse is perfectly viewable with the naked eye or binoculars.  For those who want company and commentary as to what’s going on, the Grand Traverse Astronomical Society will provide two locations from which to view the eclipse.  The NMC Observatory, south of Traverse City and Platte River Point, part of the Sleeping Bear Dunes National Lakeshore, both weather permitting.

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

Addendum

The next lunar eclipse visible from our area will be January 31, 2018 which will achieve totality just before the moon sets.  The next lunar eclipse will be January 20-21, 2019 which will start late in the evening.  The problem being that January is a pretty cloudy month around here.

We’re closer to the next solar eclipse, which will be a total eclipse visible at midday, and the center line of the path of totality which will  pass from Oregon to South Carolina, passing just south of St. Louis Missouri and north of Nashville Tennessee.  For more on the 2017 eclipse check out this NASA eclipse page.

 

09/24/2015 – Ephemeris – Looking forward to Sunday’s Lunar Eclipse

Ephemeris for Thursday, September 24th.  The Sun will rise at 7:32.  It’ll be up for 12 hours and 4 minutes, setting at 7:36.   The Moon, half way from first quarter to full, will set at 4:20 tomorrow morning.

Lets check out Sunday’s total lunar eclipse.  It will be visible from the entire contiguous United States, and in its entirety from Colorado, eastward.  The partial phase will start at 9:07 p.m.  The total phase will begin at 10:11 p.m. and extend to 11:23 p.m. when the ending partial phase will start.  The eclipse will end at 12:27 a.m.  The eclipse is perfectly viewable with the naked eye or binoculars.  For those who want company and commentary as to what’s going on, the Grand Traverse Astronomical Society will provide two venues from which to view the eclipse:  The Northwestern Michigan College’s Rogers Observatory, south of Traverse City on Birmley Rd. and Platte River Point at the end of Lake Michigan Road off M22, part of the Sleeping Bear Dunes National Lakeshore, weather permitting.

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

Addendum

The following is an excerpt from my September 1 post.

The eclipse occurs on the 28th for Universal Time. It’s the evening of the 27th for us. The Moon travels through the Earth’s shadow from right to left. What are seen are points of contact with the shadow and mid-eclipse. From Five Millennium Canon of Lunar Eclipses (Espenak & Meeus) NASA.

Contact times are labeled P1, U1, U2, U3, U4, and P4.  P2 and P3 are omitted because they are synonymous with U1 and U4 respectively:

• P1 – 8:11:47 p.m. Enter the penumbra (unseen).  By about 8:30 the duskiness on the left edge of the moon will start to be noticeable.
• U1 – 9:07:11 p.m. Enter the umbra (partial eclipse begins).
• U2 – 10:11:10 p.m. Totality begins.
• Mid eclipse 10:48:17 p.m.
• U3 – 11:23:05 p.m. Totality ends, egress partial phase begins.
• U4 – 12:27:03 a.m. Partial phase ends.  The Moon’s upper right edge should appear dusky for the next half hour or so.
• P4 – 1:22:27 a.m.  Penumbral phase ends (unseen).

Note:  The duskiness of the penumbral phase of the eclipse can be enhanced by viewing through sunglasses.

During the total phase, light leaks in around the Earth due to the bending of light in the Earth’s atmosphere, so the Moon is illuminated by the collective sunrises and sunsets around the globe.  This usually gives the Moon a coppery hue, that some are now calling a blood moon.  Occasionally, due to volcanic eruptions the Moon can become very dark.

This full moon is also the Harvest Moon and for those who care, a supermoon, it having reached perigee earlier that day.

Weather permitting there will be two GTAS venues to view this eclipse.  The first will be the NMC Rogers Observatory.  The second will be at the Sleeping Bear Dunes National Lakeshore at Platte River Point at the end of Lake Michigan Road.  The site will be open for the visible parts of the eclipse from 9 p.m. to 12:30 a.m.

09/21/2015 – Ephemeris – Next Sunday’s total lunar eclipse

Ephemeris for Monday, September 21st.  The Sun will rise at 7:28.  It’ll be up for 12 hours and 14 minutes, setting at 7:42.   The Moon, at first quarter today, will set at 1:02 tomorrow morning.

It’s six days to the total lunar eclipse next Sunday night.  The eclipse starts just after 9 p.m. and ends shortly before 12:30 a.m.  Of the remarkable four eclipse string at every possible lunar eclipse opportunity, this last one is the best for us, in that it occurs in the evening.  The others were in the morning our time or occurred around the time of moon set around here.  So if clear skies prevail we will have a wonderful and beautiful total lunar eclipse.  Lunar eclipses occur at full moon when the Sun, Earth and Moon line up close enough for the Moon to enter the Earth’s shadow.  Generally this only occurs about 1 out of 6 full moons.  Eclipses of the Sun and Moon normally appear in pairs.  The solar eclipse already occurred 8 days ago.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

NASA eclipse chart portion. In the eastern US the Date will be September 27. Subtract 4 hours from UT to get EDT (Eastern Daylight Time) Credit: NASA/ Fred Espanek.

Here’s the link to the full chart.