Archive
Ephemeris: 11/17/2025 – More about the Pleiades
This is Bob Moler with Ephemeris for Monday, November 17th. Today the Sun will be up for 9 hours and 29 minutes, setting at 5:12, and it will rise tomorrow at 7:44. The Moon, 3 days before new, will rise at 6:16 tomorrow morning.
Around 8 in the evening the marvelous small star group called the Pleiades, or Seven Sisters will be in the eastern sky. Most people can see six stars, but they’re called the Seven Sisters, so the story has come up about the Lost Pleiad. It was said that her star was dimmed because she married a mere mortal. In Greek mythology the Pleiades were the daughters of the god Atlas and Pleione. By 9 PM the hunter Orion is rising in the east to chase the Pleiades across the sky until dawn. The word Pleiades is related to the Greek word for sail, and in ancient times the sailing season in the Mediterranean Sea started with the heliacal * rising of the Pleiades at dawn in mid-spring.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
* Heliacal Rising – The first appearance in the morning of a celestial body after disappearing in evening twilight.
Addendum
Ephemeris: 11/04/2025 – The Persephone Period starts tomorrow
This is Bob Moler with Ephemeris for Election Day for some, Tuesday, November 4th. Today the Sun will be up for 10 hours and 1 minute, setting at 5:26, and it will rise tomorrow at 7:26. The Moon, 1 day before full, will set at 7:41 tomorrow morning.
Tomorrow the daylight hours drops below 10 hours. This begins something which has been called the Persephone Period. It is named after the Greek goddess Persephone, goddess of spring, who is abducted by Hades the god of the underworld to be his bride. When he did, all the vegetation on the earth began to die. So he had to allow her to appear above ground for a part of the year so that the vegetation and the grain would grow. So the Persephone Period is the time when she is in the underworld. It lasts from now to early February. That may have worked for a country like Greece around the Mediterranean, but we have harsher weather here. It takes a much longer time for spring to arrive.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 10/23/2025 – Finding Perseus the hero
This is Ephemeris for Thursday, October 23rd. Today the Sun will be up for 10 hours and 35 minutes, setting at 6:44, and it will rise tomorrow at 8:10. The Moon, 2 days past new, will set at 7:21 this evening.
About a third the way from the east northeastern horizon to the zenith at 9 p.m. and below the letter W shaped constellation of Cassiopeia the queen is Perseus the hero. It’s kind of an odd shape for a hero, To me it looks kinda like the cartoon roadrunner. To those who’re mathematically inclined its shape is also like the Greek letter pi on its side. It’s two brightest stars are Mirfak and Algol the demon star, the still winking eye of Medusa. Look at the area around Mirfak with binoculars and a large group of stars just below naked eye visibility will appear. It’s called the Alpha Persei Association. That’s because Mirfak is also known as Alpha Persei. The group is about 560 light years away, which are farther away than the Pleiades, which is below and to the right of them.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 10/21/2025 – Finding Andromeda
This is Ephemeris for Tuesday, October 21st. Today the Sun will be up for 10 hours and 41 minutes, setting at 6:47, and it will rise tomorrow at 8:07. The Moon is new today, and won’t be visible.
Tonight at 9:00 PM Saturn is in the southeast, with the Great Square of Pegasus above and to the left. Off the leftmost star of the Great Square, called Alpheratz, are two curved lines of stars to the left and a bit below, and slightly diverging. They might be mistaken for the hind legs of the horse, which is flying upside down. It’s another constellation, that of Andromeda the Princess, daughter of Cassiopeia, the W shaped constellation to the upper left. Andromeda was rescued by hero Perseus which is another constellation left of her, which we’ll get to later on this week. Andromeda’s claim to scientific fame is the large galaxy located there, the Great Andromeda Galaxy, probably the farthest thing one can spot with the naked eye.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Andromeda is part of the Great Star Story of Autumn. My take on it is linked Here.
Ephemeris: 08/25/2025 – Two fascinating constellations in and near the Summer Triangle
This is Bob Moler with Ephemeris for Monday, August 25th. Today the Sun will be up for 13 hours and 33 minutes, setting at 8:31, and it will rise tomorrow at 6:58. The Moon, 2 days past new, will set at 9:27 this evening.
There are two small constellations in and near the Summer Triangle of bright stars. Both are near Altair the bottom star of the triangle in the southeast. The first is Delphinus the dolphin to the left of Altair. Delphinus is made-up of a small squished box of stars with another star below. It does look a dolphin leaping out of the water. The legendary Greek poet Arion, according to myth, was rescued by a dolphin. Also, the little squished box is an asterism called Job’s Coffin, though no one knows the origin of that name. The second constellation is above Altair, and within the Summer Triangle. It is called Sagitta the arrow. The stars do line up to look like a short arrow. It’s supposed to represent Cupid’s dart.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 07/17/2025 – Finding the celestial eagle, Aquila
This is Ephemeris for Thursday, July 17th. Today the Sun will be up for 15 hours and 10 minutes, setting at 9:23, and it will rise tomorrow at 6:14. The Moon, at last quarter today, will rise at 12:42 tomorrow morning.
Aquila the eagle is a constellation that lies in the Milky Way. It’s in the southeastern sky as it gets dark. Its brightest star, Altair, is one of the stars of the Summer Triangle, a group of three bright stars dominating the eastern sky in the evening now. Altair, in the head of the eagle, is flanked by two slightly dimmer stars, the shoulders of the eagle. The eagle is flying northeastward through the Milky Way. Its wings are seen in the wing tip stars. A curved group of stars to the lower right of Altair is its tail. Within Aquila, the Milky Way shows many dark clouds as part of the Great Rift that splits it here. The other summer bird is Cygnus the swan above and left of Aquila, flying in the opposite direction. It was said this was the eagle that attended the god Jupiter.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 6/24/2025 – Lyra, the heavenly harp
This is Ephemeris for Tuesday, June 24th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 1 day before new, will rise at 5:36 tomorrow morning.
Fairly high in the east at 11 p.m. can be found a bright star just above a small, narrow, but very distinctive parallelogram of stars. They are the stars of the constellation Lyra the harp. The bright star is Vega, the 5th brightest nighttime star. To the Romans, the star Vega represented a falling eagle or vulture. Apparently they never made the distinction between the two species. It is a pure white star and serves as a calibration star for color and brightness. In the evening, it is the top-most star of the Summer Triangle. The harp, according to Greek mythology, was invented by the god Hermes. The form of the harp, in the sky, is as he had invented it: by stretching strings across a tortoise shell. Hermes gave it to his half-brother Apollo, who in turn gave it to the legendary musician Orpheus.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 06/19/2025 – Finding the Serpent Bearer in the heavens
This is Ephemeris for Juneteenth, Thursday, June 19th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 1 day past last quarter, will rise at 2:15 tomorrow morning.
The red star Antares shines low in the south-southeast at 11 PM in the constellation of Scorpius. In the area of sky above and to the left lies a large constellation of faint stars called Ophiuchus, the serpent bearer. The constellation shape is like a large bell, which reminds me of the head, shoulders and arms of a fellow that’s holding the snake stretched out across his body. The serpent he’s holding is Serpens, the only two-part constellation in the heavens. The head rises to Ophiuchus’ right, and the tail extends up to the left. In Greek myth, Ophiuchus represents the great physician Aesculapius, educated by the god Apollo, and the centaur Chiron, who is found in the stars as Sagittarius, just rising below him.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 05/29/2025 – Finding the celestial dragon
This is Ephemeris for Thursday, May 29th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:01. The Moon, 3 days past new, will set at 12:40 tomorrow morning.
High in the northern sky at 11 p.m. lies the twisted constellation of Draco the dragon. This dragon is more like the snakelike dragon of the Chinese New Year parades than the dinosaur-like dragon of European legend. I find it better to start at the tail of Draco, to trace him out in the stars. Draco’s tail ends between the Big and Little Dippers high in the north-northwest. The Dragon is seen in a line of stars that extends parallel to the handle of the Big Dipper before curving around the bowl of the Little Dipper then bends back down to the level of Polaris in the north-northeast before turning toward the east. The head of Draco is an odd box of stars near the bright star Vega, in the east. Though not made up of very bright stars, Draco has an easy shape to trace.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 05/22/2025 – Finding Hercules among the spring stars
This is Bob Moler with Ephemeris for Thursday, May 22nd. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:12, and it will rise tomorrow at 6:06. The Moon, 2 days past last quarter, will rise at 3:51 tomorrow morning.
In the eastern sky at 11 PM about a third of the way along the line from the bright star Vega in the east northeast and Arcturus high in the southeast is the constellation of Hercules the hero. It’s kind of hard to spot, although it’s one distinctive feature is the box of four stars called the Keystone of Hercules which means it’s wider at the top than at the bottom. That is his body. He’s upside down in the sky according to how they draw the picture of Hercules. Most of his stars are reasonably dim. This is the great hero of Greek myth. While in the winter sky the bright and splashy constellation of Orion the hunter, was kind of a hard luck hero, with no real accomplishments. Hercules has an astronomical jewel that I’ll talk about tomorrow.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Bob Moler's Ephemeris Blog 