12/30/2022 – Ephemeris – About Ephemeris

This is Bob Moler with Ephemeris for Friday, December 30th. Today the Sun will be up for 8 hours and 51 minutes, setting at 5:11, and it will rise tomorrow at 8:20. The Moon, 1 day past first quarter, will set at 2:09 tomorrow morning. | This is the last Ephemeris program of 2022. We’ve been going around the Sun together, observing the universe from spaceship Earth 47 and a half times so far. It’s been an eventful journey. And I hope to go around a few more times with you. The title of the program is Ephemeris, a word from the Greek which means diary. But to astronomers is a table of planetary positions at set intervals. The plural of ephemeris is not ephemerises, or ephemeri, but ephemerides, which sounds kind of cool. Each December, I crank up a program I wrote back in the 90s and produce ephemerides of Sun and Moon rise and set times for the next year. Also, the same for all the naked-eye planets.

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

Almanac Master database table. This is created from a file created annually by my LookingUp for MS-DOS program. The moon phase verbiage is created during the conversion process from the comma delimited file in the Ephemeris Helper program. I use this database table to create the intro to each day’s radio program.

The Holiday table is used in the intro to acknowledge that today is a special day or holiday. The Rule determines how the date is determined. F is for fixed date, D for day of week and week of month, and M for movable feast for dates based on Easter.

This is a text file produced by the Intro generated function of the Ephemeris Helper program. This file is pasted into the Ephemeris document, where I add the rest of the content. The dates with no intros are Saturday and Sunday. I also use two more files of astronomical events, which I add after the intros to help me with program topics. The intro has two formats, depending on whether the Sun rises before or after the start of the last airing of Ephemeris that day.

The intros take approximately 15 seconds, which gives me 44 seconds for the topic of the day. This gives me 59 seconds to fill a break in NPR’s Morning Edition. As far as topics go, I can’t dig deep. As far as things that can be seen in the sky: It has to be visible to the naked eye. I may talk about what might be seen in binoculars or a small telescope, but it has to be a naked eye object. You don’t need binoculars or a telescope to find it.

12/28/2022 – Ephemeris – Taking a look at the bright planets for the last week of the year

This is Ephemeris for Wednesday, December 28th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:09, and it will rise tomorrow at 8:19. The Moon, 1 day before first quarter, will set at 11:46 this evening.

Let’s see where the naked-eye planets have wandered off to this week. Mars, Jupiter and Saturn will be visible this evening, in the east to southwestern sky at 6:30 pm. Mars is in the east. Jupiter is the brightest of the three in the south, while dimmer Saturn is low in the southwest at that time. Mars is above Orion as it rises in the early evening. Saturn, the westernmost of the bright planets, will set around 8:52 this evening. Venus and Mercury are also in the evening sky, but too close to the setting Sun to be easily spotted. At 6 pm, both will be very low on the southwestern horizon, with Mercury just above Venus by three moon-widths. There are now no bright morning planets, though Mars won’t set until 6:32 am in the northwest.

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 naked eye Planets and Moon at 8 in the evening tonight, December 28, 2022. Created using Stellarium.

Waxing crescent Moon as it might appear in binoculars or low power telescope tonight, December 28, 2022. Created using Stellarium, LibreOffice Draw and GIMP

Telescopic views of Saturn Jupiter and Mars (north up) as they would be seen in a small telescope, with the same magnification. The image of Mars doesn’t show it, but the white north polar cap will appear at the top or north limb of Mars. The planets are shown at 8 pm tonight, December 28, 2022. Apparent diameters: Saturn 15.82″, its rings 36.84″; Jupiter 39.72″. Mars 15.06″. Mars’ distance is 57.8 million miles (93.0 million kilometers). The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on December 28, 2022. The night ends on the left with sunrise on the 29th. Click on the image to enlarge it. Created using my LookingUp app and GIMP.

12/27/2022 – Ephemeris – 2022: We finally saw the black hole at the center of our galaxy

This is Bob Moler with Ephemeris for Tuesday, December 27th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:08, and it will rise tomorrow at 8:19. The Moon, 2 days before first quarter, will set at 10:30 this evening.

Besides the James Webb Space Telescope coming online in July, beginning, hopefully, twenty plus years of astronomical discovery, the Event Horizon Telescope Collaboration released an image of the black hole at the center of the Milky Way, 26,000 light years away In the direction of the constellation of Sagittarius. The collaboration, which consists of eight radio telescopes spread out from Hawai’i, to Europe, from Greenland to the South Pole, observed the black hole, dubbed Sagittarius A* (Pronounced Sagittarius A Star) for hours at the same time. The signals were recorded on disc drives, synchronized by atomic clocks, and then sent to a central processing center to create the image. The image was released last May of a fuzzy donut of the black hole and its accretion disk.

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

Event Horizon Telescope component radio telescopes. Credits: © APEX, IRAM, G. Narayanan, J. McMahon, JCMT/JAC, S. Hostler, D. Harvey, ESO/C. Malin.

This is the image released May 12, 2022 by the Event Horizon Telescope Collaboration.

M87* size compared to Sagittarius A*. The size of a black hole is directly related to its mass. M87* has a mass of 6.4 billion times the Sun’s mass. It’s 55 million light years away. The mass of Sagittarius A* is only 4.2 million solar masses, and 26,000 light years away. Image credit: Event Horizon Telescope Collaboration.

Karl Jansky’s antenna reconstruction at the National Radio Astronomy Observatory, Green Bank, WV. He could rotate the antenna to find the direction of the source. He found that the source rotated with the sky, and the direction was the azimuth of the constellation of Sagittarius the archer. The source was later dubbed Sagittarius A. It is the brightest radio source in the sky. Click on the image to enlarge it. Credit: mine.

When radio astronomy was in its infancy, bright radio sources were labeled with the constellation they were in and a capital letter. Astronomers didn’t know what they really were. Karl Jansky’s discovery of the first celestial radio source in 1933 has been dubbed Sagittarius A, or Sgr A for short. He worked for Bell Labs, and was seeking the source of interference with wireless telephony transmissions. The source was from the general direction of the center of the galaxy, our Milky Way Galaxy, in the direction of the constellation of Sagittarius the archer.

12/26/2022 – Ephemeris – Some space firsts this year

This is Ephemeris for Monday, December 26th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:08, and it will rise tomorrow at 8:19. The Moon, halfway from new to first quarter, will set at 9:10 this evening.

I hope we all survived the holiday season so far. We now have one more to go, New Year’s Eve. The Moon will pass the planet Saturn later this morning. By this evening, Saturn will be to the right of the Moon in the southwestern sky. Now that we’re ending the year, we can look back at some space firsts. The James Webb Space Telescope was launched last Christmas. It became operational late spring of this year and presented its first 5 spectacular images in July. The DART spacecraft, also launched last year, collided with the small asteroid Dimorphos, orbiting the larger Didymos in a 12-hour orbit produced an amazing effect on its orbit. And late this year Artemis I finally launched, making a nearly flawless orbit of the Moon with its Orion space capsule, and returned.

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 Moon and Saturn at 6:30 pm tonight, December 26, 2022. Note that the Moon is shown at twice its apparent size to better show its phase. Created using Stellarium.

The James Webb Space Telescope teaser deep field image from President Biden’s July 11th presentation. Credit: NASA, ESA, CSA, JWST, STScI.

DART images of both Didymos, the big one, and Dimorphos, on approach. Dimorphos is the target. Credit NASA / JHAPL.

Two images from the LiciaCube satellite launched from the DART spacecraft 15 days before the impact, and trailing it to record the collision with its wide and narrow angle imagers. Dimorphos does appear to be a rubble pile asteroid from its appearance and the amount of ejecta caused by the impact. The ejecta adds to the effect of the spacecraft’s kinetic energy by pushing away from the asteroid by Newton’s third law of motion.
Credit Italian Space Agency.

Earthset from Artemis I’s Orion spacecraft, as it moves around to the far side of the Moon. Click on the image to enlarge it. Credit: NASA.

12/23/2022 – Ephemeris – Hunting for the Star of Bethlehem: Venus and Jupiter appear to merge… twice!

This is Ephemeris for Friday, December 23rd. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:06, and it will rise tomorrow at 8:18. The Moon is new today, and won’t be visible.

My favorite astronomical solution to the puzzle of the Star of Bethlehem are two conjunctions of Jupiter and Venus that occurred against the stars of the constellation of Leo the lion 10 months apart on August 12th 3 BCE and June 16th 2 BCE. Leo at that time was associated with Jacob’s son Judah and the land of Judea. The first conjunction occurred in morning twilight. The second in the evening. The first conjunction was close, though someone with excellent eyesight might pick them apart, but the second, would be impossible to separate without a telescope, which wouldn’t be invented for another 16 centuries. And Jesus would have been born in the spring during lambing season when shepherds would have been out all night with their flocks, protecting them. The eclipse that Herod died after would have been on January 10th, 1 BCE, which occurred three months before Passover, enough time for all the palace intrigue* to happen between the lunar eclipse and Passover.

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.

* See yesterday’s post for more information here.

Addendum

The Babylonian concept of the constellation Leo. They called it Urgulu, meaning lion. It represented their god Latarak. The star they called Sharru, meaning King we know as Regulus, which is the diminutive of king.

Here is an animation created using Stellarium of Jupiter and Venus, the brighter of the two seeming to coalesce on August 12, 3 BC in the early morning twilight. That ghost object that flashed on for one date was the Moon. Created using Stellarium and GIMP.

On June 16th 2 BC, this time in the evening, Venus and Jupiter seem to coalesce as one, at least to the naked eye. Created using Stellarium and GIMP.

Venus appeared among Jupiter’s moons on June 16, 2 BC. Of course, no one had a telescope back then. The telescope wouldn’t be invented for another 16 centuries. Stellarium cannot create the real brightness difference between Jupiter and Venus. Venus would be simply dazzling compared to Jupiter, being 12 times brighter. Venus, being an inner planet, shows phases like the Moon. At this time, Venus would have been near its greatest eastern elongation or separation from the Sun, so it would appear as a tiny first quarter moon. Galileo discovered that Venus had phases and orbited the Sun, in the early 17th century. Created using Stellarium.

Merry Christmas!

12/22/2022 – Ephemeris – Hunting for the Star of Bethlehem: When did Herod the Great Die – Part 2

This is Ephemeris for Thursday, December 22nd. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:05, and it will rise tomorrow at 8:17. The Moon, 1 day before new, will rise at 8:56 tomorrow morning.

According to the Gospel of Matthew, Jesus was born in the last years of the reign of Herod the Great, and the Jewish historian Josephus puts Herod’s death shortly after an eclipse of the Moon. There may have been an error in the Josephus history that has been propagated since the middle of the 16th century, that when corrected shifts the eclipse in question forward three years to 1 BCE. The conjunctions of Jupiter and Saturn of 7 BCE would be four years too early. Under this scenario, Jesus would have been born in the spring of 2 BCE, the time of year when shepherds would indeed be out at night with their flocks, because this was lambing season. What the Magi would have seen was, on two occasions, the planets Venus and Jupiter appear to merge into a single star.

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

This is a timeline I developed of the events surrounding the Birth of Jesus. On the top line in yellow are the two eclipses of the Moon that occurred in the time period we’re interested in: 4 BCE and 1 BCE. One of then was the eclipse Josephus mentions that occurred shortly before the death of Herod the Great, who was alive to greet the Magi, who came to Jerusalem seeking the newborn King of the Jews. The second line highlights 3 and 2 BCE that the early Christian writers Irenaeus, Tertullian and Clement of Alexandria based Jesus’ birth year to Roman events which can be pegged to the Roman Calendar which has a direct relationship to our own calendar. The next line contains hits based on the Crucifixion of Jesus at age 33, where the Last Supper was a Seder on the first day of Passover. The next line with C and P are two censuses of Augustus in our time period. The next to the last line shows the relation of the triple conjunction in 7 BCE with Jesus’ birth and Herod’s death. The bottom line related the two Venus-Jupiter conjunctions with Jesus’ birth and Herod’s death.

Where the lunar eclipse of March 13 of 4 BCE was a slight partial eclipse. The lunar eclipse of January 10 of 1 BCE was total, which occurred three or four months before Passover. Herod’s death and the chaos that ensued, according to Josephus, before Passover also means the March 13, 4 BCE eclipse, occurring 1 month before Passover does not provide the length of time for all these events to transpire:

• Josephus mentions an eclipse of the moon.
• Herod went beyond the river Jordan to the warm baths at Callirrhoe by the Dead Sea.
• He knew he was near death as the treatments failed, so he returned to Jericho.
• Before he did, he had his soldiers paid a bonus.
• He ordered all the principal men of the Jews to meet with him under penalty of death. Those who did come, were imprisoned at the Hippodrome to be killed upon his death.
• Herod then attempted suicide.
• Herod’s son Antipater attempted to take the throne, and was executed.
• Five days later, Herod died.
• Herod had bequeathed the kingdom to another son, Archlaus, who then organized the funeral for Herod.
• The funeral procession could have taken up to 25 days.
• Then there were 7 days of mourning after that.
• Archlaus sent his generals to Caesar on his behalf to have him declared King.
• The people were beginning to demand lighter taxes and the release of those whom Herod had imprisoned.
• At that point, Josephus mentioned that Passover was approaching.
• Finally, it was Passover.

Obviously, all these events could not be squeezed into one 29 to 30 lunar month in 4 BCE. Defenders of the 4 BCE death of Herod would say that the Passover mentioned was the next year’s Passover, giving 12 or 13 months for the events to occur. In that case, why mention Passover at all?

Missing from the timeline above is Luke’s mention of Quirinius being Governor of Syria. However, there is a problem. Luke states the at the time of Jesus’ birth that Quirinius was Governor of Syria. The problem is that he wasn’t Governor of Syria until 6 and 7 CE, at least 8 years after the events of the Nativity. And the question of who was Governor of Syria wouldn’t have mattered until 6 CE, when Judea actually became part of the Province of Syria. In the period we’re looking at, Quintilius Varus was Syria’s governor. Could the two names be switched due to a copyist error? Anyway, this was before Judea became part of Syria, so it wouldn’t have mattered who was governor of Syria when Jesus was born. Luke’s account is not much help in dating the year of Jesus’ birth.

Tomorrow, I’ll finish up with the two conjunctions of Jupiter and Venus against the stars of Leo, which was the celestial sign of Judah and the land of Judea.

12/21/2022 – Ephemeris – Winter starts today plus our weekly look at the bright planets

This is Bob Moler with Ephemeris for Wednesday, December 21st. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:05, and it will rise tomorrow at 8:17. The Moon, 2 days before new, will rise at 7:41 tomorrow morning.

Winter begins today at 4:48 pm, just before sunset, from then on until next June the 21st, the Sun, being its farthest south in our skies, will be heading northward again. Let’s see where the naked-eye planets have wandered off to this week. Mars, Jupiter and Saturn will be visible this evening, in the east to southwestern sky at 6 pm. Jupiter is the brightest of the three in the south-southeast, while dimmer Saturn is low in the south-southwest at that hour. Mars is above Orion in the east. Saturn, the westernmost of the bright planets, will set around 9:16 this evening. Venus and Mercury are also in the evening sky, but too close to the setting Sun to be easily spotted. At 6 pm, both will be very low on the southwestern horizon.

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.

Addenda

Winter solstice today

Comparing the sun’s path at the summer and winter solstices. This is a stereographic representation of the whole sky, which distorts the sky and magnifies the size of the sun’s path near the horizon. This chart is for Traverse City, Michigan, about a third of a degree south of 45º north latitude. Created using my LookingUp app.

The bright planets this week

Panoramic view of planets this evening at 7 pm, December 21, 2022. Click on the image to enlarge it. Created using Stellarium.

Telescopic views of Saturn Jupiter and Mars (north up) as they would be seen in a small telescope, with the same magnification. The image of Mars doesn’t show it, but the white north polar cap will appear at the top or north limb of Mars. The planets are shown at 7 pm tonight, December 21, 2022. Apparent diameters: Saturn 15.95″, its rings 37.15″; Jupiter 40.64″. Mars 15.92″. Mars’ distance is 54.6 million miles (88.0 million kilometers). The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on December 21, 2022. The night ends on the left with sunrise on the 22nd. Click on the image to enlarge it. Created using my LookingUp app and GIMP.

 

 

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.

12/19/2022 – Ephemeris – Hunting for the Star of Bethlehem: What it wasn’t

This is Ephemeris for Monday, December 19th. 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 past last quarter, will rise at 4:59 tomorrow morning.

In these last days before Christmas, I’d like to explore what in the sky could have been the Star of Bethlehem from an astronomical point of view. If it had to do with the arrangement of planets, tracing back two thousand years would be simple. If it was some sudden appearance of an actual star or comet, we would have to rely on contemporary accounts. Those would have to come from the Chinese and Koreans. The state of astronomy around the Mediterranean and the Middle East was pretty stagnant due to the fact that they thought that the heavens were perfect and changeless, so things like comets and novae or “New Stars” meant change, so were not really part of the heavens. So we must look for something more mundane.

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

Probably the first person to kick off the search for the Star of Bethlehem was Johannes Kepler. (These are slides from this year’s Searching for the Star of Bethlehem presentation I gave to the Grand Traverse Astronomical Society. The captions are from the text of the presentation)

The search for the Star really started with Johannes Kepler, who lived from 1571 to 1630. He was an astronomer, although he cast horoscopes for the odd prince or duke, which is how he made a living. His mother was even charged for being a witch, but nothing came of it. And after much trial and error discovered his Three Laws of Planetary Motion. His story is a fascinating one.

Kepler also discovered a supernova, the last one seen in the Milky Way. This is an old star chart that records Kepler’s Star,
a supernova, or super bright new star, he discovered on October 9, 1604. I colored it yellow and have an arrow pointed to it, in Ophiuchus’ right ankle.

Here is a Stellarium recreation of the sky the night of his discovery. It’s the southwestern sky near the end of evening twilight, October 9, 1604, the night Kepler discovered the supernova that bears his name. It got him to thinking, could a similar grouping of a nova and planets be the Star of Bethlehem?
He knew of no nova being reported back then, though no one in the western world probably would have. That would be a change in the officially changeless heavens, so it couldn’t possibly have been a real heavenly object. And being the mathematical genius he was, (he did discover the Three Laws of Planetary Motion), found a very interesting conjunction of Jupiter and Saturn, with Mars piling on later, that occurred in 7 BCE. (Click on the image to enlarge it.)

12/16/2022 – Ephemeris – The Anishinaabe constellation of Winter Maker announces the coming of winter

This is Ephemeris for Friday, December 16th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:03, and it will rise tomorrow at 8:14. The Moon, at last quarter today, will rise at 1:22 tomorrow morning. | The native peoples of the Great Lakes area are the Anishinaabe, composed of the Odawa or Ottawa, and Chippewa or Ojibwe tribes. One of their great constellations is the Winter Maker, whose central part we know as Orion. Instead of turning to face the charge of Taurus the bull, holds his arms outstretched to embrace all the winter stars. His rising in November foretells the coming of winter. His name in their Anishinaabemowin language means North Wind. Now that winter is almost here, he is moving to the southern part of the sky in the evening to reign over the brilliant stars of winter. The star we call Sirius, the brightest nighttime star, is called Gizhii’anung. Anung means “star”.

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 Anishinaabe constellation of the Winter Maker, whose arms will encompass the rest of the winter stars, once they rise later in the evening. Also shown is the Hole in the Sky, which we know as the Pleiades.