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Ephemeris: 01/23/2025 – Conflict in the heavens
This is Ephemeris for Thursday, January 23rd. Today the Sun will be up for 9 hours and 28 minutes, setting at 5:39, and it will rise tomorrow at 8:09. The Moon, 2 days past last quarter, will rise at 4:15 tomorrow morning.
There are several instances in the Greek heavens where constellations appear to interact with one another. This is true with Orion the hunter and Taurus the bull. Taurus, whose face is the letter V of stars, near Jupiter this year. The orangish star Aldebaran as his angry bloodshot eye is charging down on Orion, who has raised a lion skin shield on one arm and an upraised club in the other, ready to strike. They have been frozen in this pose for millennia. Stars below and right of the letter V of the Bull’s face suggest the front part of his body and his front legs charging at Orion. Orion also has two hunting dogs, Canis Major and Canis Minor. Canis Major with its dazzling star Sirius will rise around 6:21 on a line extending down from Orion’s belt.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.
Addendum
Perhaps Jupiter is not intruding, because the Roman god Jupiter is the Greek god Zeus, who turned himself into a bull to carry off the maiden Europa. And Europa is with him still as Jupiter’s moon, and target of NASA’s recently launched Europa Clipper spacecraft.
Ephemeris: 12/27/2024 – Orion’s story
This is Ephemeris for Friday, December 27th. 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, 3 days before new, will rise at 6:32 tomorrow morning.
It may seem unfair that the greatest mythological hero Hercules gets a little constellation of dim stars on the border between the spring and summer constellations, while Orion, a virtual nobody, a hard luck hero gets the splashiest constellation in the sky. Orion’s claim to fame or infamy is how he died. And the Greeks had two completely different stories on how that happened. First, that he was killed by a sting of a giant scorpion represented by the constellation Scorpius, and second that he was killed by an arrow shot by the goddess he loved, the arrow being deflected by her brother who didn’t want her to marry a mere mortal.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.
Addendum
Ephemeris: 11/25/2024 – How to find Taurus the bull
This is Ephemeris for Monday, November 25th. Today the Sun will be up for 9 hours and 12 minutes, setting at 5:06, and it will rise tomorrow at 7:54. The Moon, 3 days past last quarter, will rise at 3:15 tomorrow morning.
Low in the east at 8 this evening and below the beautiful Pleiades star cluster is Taurus the bull. His face is a letter V shape of stars lying on its side, the star cluster Hyades, with the bright orange-red star Aldebaran at one tip of the V as its angry bloodshot eye. Aldebaran is actually about halfway between us and the cluster. Tonight it is to the right of the brilliant planet Jupiter. The Pleiades star cluster is in his shoulder. Taurus is seen charging downward at that hour, the rising constellation of Orion. Taurus in Greek mythology was the form the god Zeus assumed when he carried off the maiden Europa. Europa’s still with him as a moon orbiting Zeus’ Roman equivalent, the planet Jupiter.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.
Addendum
Ephemeris: 09/27/2024 – Finding Andromeda
This is Ephemeris for Friday, September 27th. Today the Sun will be up for 11 hours and 53 minutes, setting at 7:29, and it will rise tomorrow at 7:37. The Moon, 3 days past last quarter, will rise at 3:11 tomorrow morning.
The constellation of Andromeda is famous mainly for the galaxy visible to the naked eye that is contained within it, called the Great Andromeda Galaxy, which is actually visible to the naked eye. Andromeda is found in the east northeast these evenings connected to the Great Square of Pegasus, the square of stars standing on one corner in the east. It shares a star with that square called Alpheratz, the leftmost star, and from that star two curved lines of stars are seen to the left that is the body of Andromeda. She was a Princess and daughter of Queen Cassiopeia, and was fated to be devoured by the monster Cetus. She was saved by the hero Perseus who flew in on his flying horse Pegasus.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 08/02/2024 – The Northern Cross
This is Ephemeris for Friday, August 2nd. Today the Sun will be up for 14 hours and 35 minutes, setting at 9:06, and it will rise tomorrow at 6:31. The Moon, 2 days before new, will rise at 5:12 tomorrow morning.
The star Deneb is high in the east-northeast. It is the dimmest of the three stars of the Summer Triangle. It is at the head of the Northern Cross, an informal constellation or asterism. The upright extends to the South. The crossbeam can be seen crossing the star just south of Deneb. There’s also a constellation there. It’s actually Cygnus the swan flying southward along the Milky Way with its neck outstretched. The Anishinaabe natives peoples of our area see Ajijaak the crane, also with a long neck flying north, but also long legs trailing to the south, its wings outstretched. In Greek mythology Cygnus was the guise of the god Zeus when he seduced Leda, whose offspring was Pollux, one of the Gemini twins.
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
Ephemeris: 07/30/2024 – The heavenly harp
This is Ephemeris for Tuesday, July 30th. Today the Sun will be up for 14 hours and 42 minutes, setting at 9:10, and it will rise tomorrow at 6:28. The Moon, 3 days past last quarter, will rise at 2:08 tomorrow morning.
After it gets dark, nearly overhead, appears the bright star Vega, the brightest of the stars of the Summer Triangle. It is part of the constellation called Lyra the harp. The form of the harp is a lyre, which has a U-shaped frame with a bar across the top, the strings are strung from the bar down to the base of the U. According to Greek myth it was invented by the god Hermes who used a tortoise shell as the base of the U. He gave it to Apollo, who in turn gave it to Orpheus. Orpheus had the greatest musical talent. His singing and lyre playing would make animals and even inanimate objects dance. The constellation itself consists of Vega and a parallelogram of four stars which are seen below it.
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
Ephemeris Extra: 07/02/2024 – A closer look at Corona Borealis
Adapted from an article that ran in the Stellar Sentinel, the July 2024 newsletter of the Grand Traverse Astronomical Society.
A small constellation is getting a lot of attention this year because we expect a bright nova to appear in it sometime in the next few months. The constellation is Corona Borealis, the Northern Crown. It is a small constellation between the Boötes and the bright star Arcturus and Hercules, and farther off to the east the bright star Vega. Corona Borealis contains seven stars in the 2/3 circle of stars. Its brightest star is the third star from the right. It’s the second magnitude star called Alphecca. In Arabic, it means The Bright Star of the Broken Ring of Stars, which is a pretty good description of it. It is also known as Gemma though it sounds like a gem in a crown, it actually means blossom which would appear in a floral crown.
In Greek mythology the crown was given to the Princess Ariadne. The story goes like this. During the time of the Minoan civilization on Crete, It was ruled by King Minos, whose daughter was Ariadne. The Minoans apparently had defeated Athens in battle and had extracted tribute from them. That yearly tribute being the sacrifice of the young man or maiden to enter the Labyrinth which was home to a monster called the Minotaur. In this story a fellow by the name of Theseus from Athens was sent to Crete to face the Minotaur. He fell in love with Ariadne, but he had to enter the Labyrinth, so she provided him with a spool of thread so he could find his way back out again after he had slain the Minotaur, if he was able to. He entered the Labyrinth and found the Minotaur. Theseus was able to slay the beast, and was able to follow the thread back out. Theseus and Ariadne fled to the Island of Naxos where he married her. However, he soon abandoned her. As consolation, the god Dionysus gave her a crown. She kept the crown until she remarried, and it was placed in the sky where we see it today.
For the Anishinaabe native peoples of our area Corona Borealis becomes the Sweat Lodge. Other indigenous peoples of North America see these stars as circles of maidens, or other circles. To the Aborigines of Australia who see Corona Borealis very low in the north, it’s Woomera, the boomerang.
The constellation has two famous variable stars. The one we’re expecting to flare up this year, up to second magnitude as a nova, is T Coronae Borealis (T CrB), sometimes called the Blaze Star. It was recorded in 1866 and at even earlier times, and was naked eye for eight days, dropping a half magnitude per day. It also blazed forth in 1946, making it one of the few known recurrent novas. In 1946 the star, normally 10th magnitude, barely visible in binoculars, underwent a slight dimming about 11 months before it blazed forth as a nova. This has already happened last year, so we are expecting it soon to blaze forth again. It will appear to the lower left, just outside the circle of stars in the crown, and will grow as bright as Alphecca.
Novas, also in the case of T CrB, are close binary stars containing a large star and a white dwarf. A white dwarf is a star at the end of its life, and has run out of hydrogen or other light elements in its core to keep it sustained. So it shrinks down to about the size of the Earth, even though it has the mass of the Sun or a little more. It orbits with the larger star and is basically siphoning off gas from that large star onto its surface, enough gases accumulate on the star for a thermonuclear reaction to occur, and it becomes a nova, brightening thousands of times for a few days. The white dwarf survives to do it all over again in some cases.
Corona Borealis’ other famous variable star is R Coronae Borealis, a star that’s normally about 6th magnitude that irregularly dips down to 10th or even dimmer. The mechanism for this appears to be that the star is surrounded by clouds of dust that periodically block it from our view.
If you’re interested in observing variable stars, check out the American Association of Variable Star Observers: https://www.aavso.org/
If there’s a Northern Crown, there should be a Southern Crown, and there is. It is Corona Australis made of dim stars, and it is located just below the constellation of Sagittarius, right below the Teapot asterism, which is very low on our southern horizon after midnight this month, but better seen in August.
Ephemeris: 05/30/2024 – Virgo and what’s hidden within
This is Bob Moler with Ephemeris for Thursday, May 30th. Today the Sun will be up for 15 hours and 18 minutes, setting at 9:20, and it will rise tomorrow at 6:00. The Moon, at last quarter today, will rise at 2:52 tomorrow morning.
One of the large constellations we see in the south at 11 p.m. can be found using the Big Dipper overhead, follow the arc of the handle to the bright star Arcturus, then straighten the arc to a spike to reach Spica, a bright blue-white star in the south. Spica is the brightest star in the constellation Virgo, the virgin. She represents the goddess of the harvest, Virgo is holding a sheaf of wheat in depictions of her, and Spica is placed at the head of the sheaf. In the space between Spica and Leo the lion to her upper right is, a great cluster of thousands of galaxies just below naked eye visibility. The Virgo Cluster. Inside that cluster is galaxy M87, in whose center lies a black hole with the mass of 6.5 billion suns. The center of the cluster is at about 54 million light years away. The first black hole imaged by the Earth spanning Event Horizon Telescope.
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
Ephemeris: 05/28/2024 – Finding Spica and Virgo
This is Ephemeris for Tuesday, May 28th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 2 days before last quarter, will rise at 2:06 tomorrow morning.
The Big Dipper, near the zenith at 10:30 pm points to several stars and constellations. It’s handle points to two bright stars. First we follow the arc of the handle to the bright orange star Arcturus, the 4th brightest nighttime star. The reason I say nighttime is that the Sun is a star also, but by definition is not out at night. The arc to Arcturus is a way to find Arcturus and a clue to its name. Arcturus, high in the south-southeast, lies at the base point of the kite shaped constellation of Boötes the herdsman. From Arcturus, straighten out the arc to a spike and one soon arrives at Spica a blue-white star in Virgo the virgin, now in the south. Spica is also sometimes pronounced ‘Speeka’.
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
Ephemeris: 05/27/2024 The evening sky is transitioning into summer
This is Bob Moler with Ephemeris for Memorial Day, Monday, May 27th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:17, and it will rise tomorrow at 6:02. The Moon, 3 days before last quarter, will rise at 1:36 tomorrow morning.
The sky tonight at 10:30 is beginning to show the transition from spring to summer. Antares in Scorpius is very low in the southeast, rising and chasing away Orion who has disappeared in the West. According to Greek mythology, at least in one story, Orion was killed by the sting of a giant scorpion and so neither he nor Scorpius the scorpion can be in the sky at the same time. The bright star Spica in Virgo the virgin is due South at that time, with Leo the lion in the southwest. Very high in the southeast is the star Arcturus. The Big Dipper is overhead. And in the east-northeast high up this is the bright star Vega, one of the stars of the summer triangle. The second star of the triangle Deneb is lower in the northeast. The third star has yet to rise.
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
Bob Moler's Ephemeris Blog 