Archive
Ephemeris: 07/20/2023 – How Boötes and Ursa Major got into the sky
This is Ephemeris for Thursday, July 20th. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:21, and it will rise tomorrow at 6:17. The Moon, 3 days past new, will set at 11:16 this evening.
Seen in high in the west-southwest at 10:30 this evening is the kite shaped constellation of Boötes (pronounced Bo-o-tees) the herdsman. The bright star Arcturus is at the bottom of the kite. It is pointed to by the arc of the handle of the Big Dipper, part of Ursa Major, the Great Bear, over toward the northwest. Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus, the chief of the Greek gods. Zeus’ wife, Hera, found out about it, and since she couldn’t punish Zeus, turned the poor woman into a bear. Arcas, many years later, unaware of the events surrounding his mother’s disappearance, was about to kill the bear when Jupiter intervened and placed them both in the sky to save her. Arcas still pursues her across the sky nightly.
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
07/13/2023 – Ephemeris – How to find Ophiuchus the serpent bearer
This is Ephemeris for Thursday, July 13th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:27, and it will rise tomorrow at 6:10. The Moon, halfway from last quarter to new, will rise at 3:04 tomorrow morning.
The red star Antares shines in the south at 11 p.m. In the constellation of Scorpius. In the area of sky above and a little 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-like a weight lifter pulling up a heavy barbell. 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, now rising below and left of him.
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
06/19/2023 – Ephemeris – Juneteenth and the flight to freedom
This is Bob Moler with Ephemeris for Juneteenth, Monday, June 19th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, 1 day past new, will set at 11:22 this evening.
In 1865, it was on June 19th that the Union soldiers, led by Major General Gordon Granger, landed at Galveston, Texas with news that the war had ended and that the slaves were now free. Until then about the only path to freedom for the slaves was “To follow the Drinking Gourd”, or the Big Dipper, northward. The Big Dipper and the Great Bear, Ursa Major, has, for the last few millennia been the constellation of the north, being closer to the North Pole of the sky than it is now. The Earth’s axis has a slow wobble, called precession, caused by the gravitational pull of the Moon and Sun on Earth’s slight equatorial bulge of 30 miles wider than the pole to pole distance. That wobble period is nearly 26 thousand years.
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
06/12/2023 – Ephemeris -Finding Hercules among the stars
This is Ephemeris for Monday, June 12th. Today the Sun will be up for 15 hours and 31 minutes, setting at 9:28, and it will rise tomorrow at 5:56. The Moon, 2 days past last quarter, will rise at 3:13 tomorrow morning.
Orion, the hard luck mythical Greek hunter, gets a splashy constellation in the winter sky, but the greatest hero of all, Hercules, gets a dim group of stars on the border between the spring and summer stars. At 11 p.m. Hercules is high in the east-southeast. It is located above and right of the bright star Vega, in the east. Hercules’ central feature is a keystone shaped box of stars, called, of course, the Keystone of Hercules tilted to the left, which represents the old boy’s shorts. From the top and left corner stars extend lines of stars that are his legs, from the bottom and right stars, the rest of his torso and arms extend. So in one final indignity, he’s upside down in our sky. For those with a telescope, Hercules contains the beautiful globular star cluster Messier 13.
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
06/09/2023 – Ephemeris – How to find Corona Borealis, the Northern Crown
This is Bob Moler with Ephemeris for Friday, June 9th. Today the Sun will be up for 15 hours and 29 minutes, setting at 9:27, and it will rise tomorrow at 5:57. The Moon, 1 day before last quarter, will rise at 2:13 tomorrow morning.
High in the southeast at 11 p.m. can be found a small but easily spotted constellation of Corona Borealis, the Northern Crown. It is located just east or left of the kite shaped constellation of Boötes, with its bright star Arcturus at the bottom. The Northern Crown is a three-quarters circle of stars, like a tiara, with a brighter star Alphecca at the bottom. Alphecca in Arabic means “Bright star of the broken ring of stars”. According to Greek mythology it belonged to Princess Ariadne, daughter of King Minos of Crete who helped Theseus escape from the Labyrinth of the Minotaur, only to be abandoned by him on an island. To the Native Chippewa and Ottawa of our area it is the Sweat Lodge.
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
Next Monday I will post about Hercules.
05/16/2023 – Ephemeris – Regulus, the Little King Star
This is Ephemeris for Tuesday, May 16th. Today the Sun will be up for 14 hours and 51 minutes, setting at 9:05, and it will rise tomorrow at 6:12. The Moon, 3 days before new, will rise at 5:08 tomorrow morning.
Regulus is the brightest star in the constellation of Leo, the lion at the bottom of the backward question mark that is the head and mane of Leo. It’s in the southwest at 10 pm. Alluding to the lion’s status in the animal kingdom, Regulus is the little king star. It is dead last in order of brightness of the 21 brightest first magnitude stars, 1/13th the brightness of Sirius the brightest nighttime star, now lost in the evening twilight glow. To the Babylonians it was the king, the 15th of their constellations, that marked the passage of the Sun. Regulus is about 79 light years away, and 288 times the brightness of the sun. It is a rapidly spinning ellipsoid 3 times the sun’s diameter, rotating in just under 16 hours.
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
Regulus and Leo and the other stars and planets in the western sky at 11 pm, May 16, 2023. Created using Stellarium.
05/15/2023 – Ephemeris – Why are crows black?
This is Bob Moler with Ephemeris for Monday, May 15th. Today the Sun will be up for 14 hours and 49 minutes, setting at 9:04, and it will rise tomorrow at 6:13. The Moon, 3 days past last quarter, will rise at 4:47 tomorrow morning.
The small constellation of Corvus the crow is located low in the south at 10:30 this evening. It’s made of 6 dim stars, the pattern is a distinctive but distorted box with two stars in the upper left corner and two stars in the lower right corner. To the right is a fainter constellation of a thick stemmed goblet called Crater. Both appear above the long constellation of Hydra, the water snake who is slithering above the southern horizon. In Greek mythology Corvus, then white, was the god Apollo’s pet who once bid the crow to take a cup and fetch him some water. Corvus, however, dallied and waited for a green fig to ripen. Corvus then grabbed a snake and returned with a story on how the snake had delayed him. The angry Apollo saw through the story and turned the crow black.
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
Corvus, Crater and Hydra finder chart. The chart was made for earlier in the month, so when it’s dark enough to see them, the constellations will have shifted to the west or right. Created using Stellarium and GIMP.
05/12/2023 – Ephemeris – Finding Virgo the virgin in the evening sky
This is Ephemeris for Friday, May 12th. Today the Sun will be up for 14 hours and 42 minutes, setting at 9:00, and it will rise tomorrow at 6:17. The Moon, at last quarter today, will rise at 3:44 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 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
Finding Virgo from the Big Dipper at 11 pm, May 12. There are no planetary interlopers this year. The small + sign marks the zenith, and the image faces south. Created using my LookingUp app, with captions added using LibreOffice Draw.
Virgo finder animation with Leo added as an aid for 11 p.m. tonight. Created using Stellarium and GIMP.
Markarian’s Chain, a small part of the Virgo Cluster of galaxies. Click or tap on the image to enlarge it. Credit: Daniel Dall’Olmo.
05/11/2023 – Ephemeris – Finding Hydra the water snake
This is Ephemeris for Thursday, May 11th. Today the Sun will be up for 14 hours and 40 minutes, setting at 8:59, and it will rise tomorrow at 6:18. The Moon, 1 day before last quarter, will rise at 3:17 tomorrow morning.
Low in the south and southwestern sky at 10 p.m. and later can be found the constellation of Hydra the water snake, the longest constellation of all. Unlike the monster of the same name, this Hydra has but one head, which is its most distinctive part. At 11 p.m. the head of Hydra is located between the bright stars Procyon in the west and Regulus in Leo the lion in the southwest. Hydra’s head is a small but distinctive group of 6 stars that make a drooping loop to the right. The rest of Hydra wends its way above the southern horizon below the bright blue star Spica in Virgo. Some delineations of Hydra have the tail tickling the constellation Libra, the balance which has just risen in the southeast.
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
Finding Hydra, the water snake animation showing nearby constellations and stars mentioned in the program. Click or tap on the image to enlarge it. Created using Stellarium, and GIMP.
05/08/2023 – Ephemeris – How to find Leo the lion in the sky
This is Ephemeris for Monday, May 8th. Today the Sun will be up for 14 hours and 32 minutes, setting at 8:56, and it will rise tomorrow at 6:22. The Moon, 3 days past full, will rise at 12:57 tomorrow morning.
At 10 p.m. the spring constellation of Leo the lion will be high in the south. It can be found by locating the Big Dipper high overhead and imagining that a hole were drilled in the bottom of the bowl to let the water leak out. It would drip on the back of this giant cat. The Lion is standing or lying facing westward. His head and mane are seen in the stars as a backwards question mark. This group of stars is also called the sickle. The bright star Regulus is at the bottom, the dot at the bottom of the question mark. A triangle of stars, to the left of Regulus, is the lion’s haunches. Leo contains some nice galaxies visible in moderate sized telescopes. The stars in Leo’s part of the sky are fewer than those in the winter sky.
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
Finding Leo the lion from the Big Dipper with no lines. The orientation is for 10 pm, May 8th. Can you find Leo? The Big Dipper? Created using Cartes du Ciel (Sky Charts).
Using the Big Dipper to find Leo. The orientation is for 10 pm on May 8th. For any other time, the orientation would be different, as would the position of the zenith (overhead point). Created using my LookingUp app.
Leo, with drawing of a lion. Created using Stellarium.
Note the star at the left end of Leo is named Denebola. There are several stars that start with “Deneb”. Deneb must mean tail in Arabic because most star names are Arabic in origin. Denebola is the tail of the lion. Deneb Kaitos is the tail of the autumn constellation of Cetus the whale, and Deneb itself is the tail of the summer constellation of Cygnus the swan.
Bob Moler's Ephemeris Blog 