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Posts Tagged ‘Cassiopeia’

09/09/2021 – Ephemeris – The constellation of Cassiopeia the Queen

September 9, 2021 Comments off

This is Ephemeris for Thursday, September 9th. Today the Sun will be up for 12 hours and 49 minutes, setting at 8:04, and it will rise tomorrow at 7:16. The Moon, 3 days past new, will set at 9:40 this evening.

Tonight, check out the crescent Moon, with Venus below left of it. Cassiopeia is a constellation shaped like the letter W seen in the northeast these evenings. In Greek mythology, she was the queen of Ethiopia. She was very beautiful and very boastful of that fact. She even compared her beauty with that of the sea nymphs, daughters of the sea god Poseidon. Papa was not amused. So Cassiopeia’s daughter, the Princess Andromeda, was made to suffer for it. Poseidon sent a sea monster, Cetus, to ravage the coastal cities of the country. The only way to stop it was to sacrifice Andromeda to the monster. Andromeda and Cetus are constellations we’ll meet in the coming weeks. We’ve already met Pegasus, the flying horse, rising in the east. And we are yet to meet the hero, Perseus.

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

Venus and te Moon in evening twilight

Venus and the Moon in evening twilight, about a half hour after sunset tonight, September 9, 2021. Created using Stellarium.

Cassiopeia finder animation

Cassiopeia finder animation looking northeast in mid-September, an hour and a half after sunset. Created using Stellarium.

 

09/07/2021 – Ephemeris – The constellation of Cepheus the king

September 7, 2021 Comments off

This is Bob Moler with Ephemeris for Tuesday, September 7th. Today the Sun will be up for 12 hours and 55 minutes, setting at 8:07, and it will rise tomorrow at 7:13. The Moon, 1 day past new, will set at 8:53 this evening.

There’s a faint constellation in the northeast above the W shaped constellation of Cassiopeia. It’s a nearly upside down church steeple of a constellation called Cepheus the king, and husband of queen Cassiopeia. Cepheus’ claim to modern astronomical fame is that one of its stars, Delta (δ) Cephei, is the archetype for the important Cepheid variable stars. Delta is the bottom most of a trio of stars at the right corner of the constellation. In the early 20th century, Henrietta Leavitt discovered that Cepheids in the nearby galaxy the Large Magellanic Cloud varied in brightness with a period that was related to their average brightness. This meant that Cepheids could be used as standard candles to measure the great distances to other galaxies.

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

Cassiopeia and Cepheus finder animation

Cassiopeia and Cepheus finder animation looking in the northeast at 9-10 pm or about an hour after sunset. Created using Stellarium and GIMP.

Delta Cephei finder for September at 9-10 pm, looking northeast. Created using Cartes du Ciel (Sky Chart).

Delta_Cephei_lightcurve

Light Curve of Delta Cephei. The pulsation period is 5.367 days. Note the Magnitude vertical axis, the lower the magnitude the brighter the star is. Blame that on the Greek astronomer Hipparchus, 2nd century BC. It’s like golf scores, the lower the score, the better the golfer. Credit: Thomas K Vbg – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=13887639.

08/30/2021 – Ephemeris – “W”

August 30, 2021 Comments off

This is Bob Moler with Ephemeris for Monday, August 30th. Today the Sun will be up for 13 hours and 19 minutes, setting at 8:22, and it will rise tomorrow at 7:04. The Moon, at last quarter today, will rise at 12:26 tomorrow morning.

Rising higher each evening in the northeastern sky is a group of stars that make the pattern of the letter W. It is the constellation of Cassiopeia the queen. It is one of the more recognizable star patterns. From our latitude here in Northern Michigan, it is circumpolar, meaning that it never sets. Though, the best time to see it is in the autumn and winter, when it’s highest in the sky. It is opposite the Big Dipper from Polaris, the north star. In fact, a line drawn from any of the handle stars of the Big Dipper through Polaris will reach Cassiopeia. So as the Big Dipper descends in the northwestern sky now, Cassiopeia ascends in the northeast. They change places in winter and spring as the Big Dipper ascends in the northeast.

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

Big Dipper-Cassiopeia animation

Animation showing the juxtaposition of Cassiopeia and the Big Dipper from Polaris, the North Star. Click on the image to enlarge it. Created using Stellarium and GIMP.

10/08/2020 – Ephemeris – A lady with a not so hidden jewel

October 8, 2020 Comments off

This is Ephemeris for Thursday, October 8th. Today the Sun will be up for 11 hours and 19 minutes, setting at 7:09, and it will rise tomorrow at 7:51. The Moon, 1 day before last quarter, will rise at 11:09 this evening.

The stars of the constellations Andromeda the chained princess look like they’re supposed to be the hind legs of Pegasus the flying horse which is high in the southern sky above Mars at 9 p.m. Andromeda is high in the southeast She is seen in the sky as two diverging curved strings of stars that curve to the left and up from the upper leftmost star of the Great Square of Pegasus. Her predicament was caused by her boastful mother Cassiopeia, and the wrath of the god Poseidon. She was rescued by the hero Perseus, a nearby constellation, riding his steed Pegasus. Andromeda’s claim to astronomical fame is the large galaxy barely visible to the unaided eye just above the upper line of stars, the Great Andromeda Galaxy 2.5 million light years away.

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

Addendum

Andromeda and M31 animated finder

Andromeda animated finder, including the Great Andromeda Galaxy. I’ve added Cassiopeia that some folks use to find the galaxy. I start with the leftmost star of the Great Square of Pegasus that connects to Andromeda. I count off two star on the lower curve because they are brighter than the upper curve. Then count two stars up. Next to that top star is a little smudge. That is the core of the Great Andromeda Galaxy. Created using Stellarium and GIMP.

The Great Andromeda Galaxy (M31). Image taken by Scott Anttila.

The Great Andromeda Galaxy (M31) and two of its satellite galaxies M31 (left) and M110. Image taken by Scott Anttila.

 

09/18/2020 – Ephemeris – A closer look at Cepheus the king’s most famous star

September 18, 2020 Comments off

This is Ephemeris for Friday, September 18th. Today the Sun will be up for 12 hours and 20 minutes, setting at 7:46, and it will rise tomorrow at 7:27. The Moon, 1 day past new, will set at 8:52 this evening.

There’s a faint constellation in the northeast above the W shaped constellation of Cassiopeia. It’s a nearly upside down church steeple of a constellation called Cepheus the king, and husband of queen Cassiopeia. Cepheus’ claim to astronomical fame is that one of its stars, Delta (δ) Cephei, is the archetype for the important Cepheid variable stars. Delta is the bottom most of a trio of stars at the right corner of the constellation. In the early 20th century Henrietta Leavitt discovered that Cepheids in the nearby galaxy the Large Magellanic Cloud varied in brightness with a period that was related to their average brightness. This meant that Cepheids could be used as standard candles to measure the great distances to other galaxies.

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

Addendum

Cassiopeia and Cepheus finder animation

Cassiopeia and Cepheus finder animation looking in the northeast at 9 pm or about an hour after sunset in mid-September. Created using Stellarium and GIMP.

Delta Cephei (circled) finder for mid-September at 9 pm or about an hour after sunset looking northeast. The brighter stars are marked by their Bayer Greek letters. Numerical designations are Flamsteed numbers. Created using Cartes du Ciel (Sky Chart).

Delta_Cephei_lightcurve

Light Curve of Delta Cephei. The pulsation period is 5.367 days. Credit: ThomasK Vbg – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=13887639

09/17/2020 – Ephemeris – Finding Cassiopeia the queen and Cepheus the king

September 17, 2020 Comments off

This is Ephemeris for Thursday, September 17th. Today the Sun will be up for 12 hours and 24 minutes, setting at 7:48, and it will rise tomorrow at 7:25. The Moon is new today, and won’t be visible.

The stars of the autumn skies are slowly replacing the summer stars from the east. Look midway up in the northeastern sky in the evening and you can find the W shaped constellation of Cassiopeia the queen. Cassiopeia is so far north that it never sets for us in Michigan. It is opposite the pole star Polaris from the handle of Big Dipper. There’s a dim star that appears above the middle star of the W which turns it into a very crooked backed chair, Cassiopeia’s throne. Above and left of Cassiopeia is a dim upside down church steeple shaped constellation of Cepheus the king, her husband. The Milky Way flows through Cassiopeia toward the northeastern horizon. She is a character in an autumn star story with five other constellations.

For my retelling of the Greek myth that links these autumn constellations click here.

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

Addendum

Cassiopeia and Cepheus finder animation

Cassiopeia and Cepheus finder animation looking in the northeast at 9 pm or about an hour after sunset in mid-September. Created using Stellarium and GIMP.

 

09/07/2020 – Ephemeris – A first look at the autumn stars arriving: Cassiopeia and Pegasus

September 7, 2020 Comments off

This is Ephemeris for Labor Day, Monday, September 7th. Today the Sun will be up for 12 hours and 54 minutes, setting at 8:07, and it will rise tomorrow at 7:14. The Moon, 3 days before last quarter, will rise at 10:46 this evening.

In the evening as summer wanes and the Sagittarius teapot tips its contents on the southwestern horizon the constellations of autumn rise in the east. There’s the W shape of Cassiopeia in the northeast, which is so far north it never really leaves us in northern Michigan. Pegasus the flying horse of Greek mythology is perhaps the most famous of the autumn constellations, and easiest to find. Its body, a large square of four stars, is in the east, standing on one corner. It is known as the Great Square of Pegasus. Only the front half of the horse is in the sky, and he’s flying upside down with his neck and head extending to the right from the rightmost star. His galloping front legs extend upward from the top star.

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

Addendum

NE to SW Panorama

Northeast to southwest Panorama around the horizon at 10 pm tonight, September 7, 2020 showing the constellations discussed. Click on the image to enlarge. Created using Stellarium and GIMP.

 

08/11/2020 – Ephemeris – Tonight is the peak of the Perseid Meteor shower

August 11, 2020 Comments off

This is Bob Moler with Ephemeris for Tuesday, August 11th. Today the Sun will be up for 14 hours and 12 minutes, setting at 8:53, and it will rise tomorrow at 6:42. The Moon, at last quarter today, will rise at 12:46 tomorrow morning.

This evening and tomorrow morning we should see the peak of the Perseid Meteor Shower. There is the expected broad peak of the shower which for us is after sunrise. However the meteoroid stream isn’t monolithic. Each pass of the comet in the inner solar system superimposes its debris on the general stream, so we will have increased activity all night tonight and even into the next few mornings. In general Perseid meteors will be seen to come from the northeast. The evening view will be not hampered by the Moon until it rises at 12:46 am which will drown out the dimmer meteors. The best time to view is from about 10 or 10:30 pm to 12:46 am. The Perseids are the most active meteor shower visible in warm weather, with a possible over 50 meteors per hour.

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

Addendum

My best Perseid photo. From the 70's.

My best Perseid photo. From the 1970’s.

Perseid radiant at 11 pm, August 11th

Perseid radiant at 11 pm, August 11th at the top of the constellation of Perseus, below the W shaped constellation of Cassiopeia. Click on the image to enlarge. Created using Stellarium.

09/24/2019 – Ephemeris – Cassiopeia the “W” shaped constellation

September 24, 2019 Comments off

Ephemeris for Tuesday, September 24th. Today the Sun will be up for 12 hours and 4 minutes, setting at 7:36, and it will rise tomorrow at 7:33. The Moon, 3 days past last quarter, will rise at 3:13 tomorrow morning.

The stars of the autumn skies slowly are replacing the summer stars from the east. Look in the northeastern sky by 9 p.m. and you can find the W shaped constellation of Cassiopeia the queen. Cassiopeia is so far north that it never sets for us in Michigan. It is opposite the pole star Polaris from the Big Dipper. There’s a dim star that appears above the middle star of the W which turns the W into a very crooked backed chair. Cassiopeia, in Greek mythology, represents a queen of ancient Ethiopia, the W represents the profile of her throne. She enters in to the great autumn story whose other characters are also seen in the stars as the constellations Andromeda, Pegasus, Perseus, Cetus and her husband Cepheus.

For my retelling of the Greek myth that links these autumn constellations click here.

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

Addendum

Cassiopeia finder

Cassiopeia, in the northeast is opposite Polaris from the Big Dipper. For 9 p.m. in late September. Created using Stellarium. Artistic credit: Johan Meuris.

Ephemeris Extra – The Great Star Story of Autumn

September 18, 2019 Comments off
Autumn Star Story Constellations

The constellations of the great star story of autumn. Looking southeast on October 31 at 10 p.m. Created using Stellarium.

The great star wheel of the sky rolls on. In the evening sky gone are the stars of spring, and going are the southern stars of summer. In the morning sky before sunrise the stars of an early winter evening.

A constant in both skies are the stars of autumn: rising in the evening and setting in the morning. In no other part of the sky do so many constellations take part in a single story

The constellations, as seen above are Cepheus, Cassiopeia, Andromeda, Perseus, Pegasus, and Cetus. And their story goes like this:

In distant Ethiopia a crisis was brewing. King Cepheus and Queen Cassiopeia were at wits end as how to stop it. A giant sea monster named Cetus was ravaging the country’s coastal cities destroying them and devouring the inhabitants.

The king and queen consulted the temple oracle as to what happened and what could be done to save their country. The oracle intoned gravely that the fault was Cassiopeia’s. Suddenly the queen knew what happened. Cassiopeia was very beautiful and she had vainly boasted to all who could hear that she was more beautiful than even the sea nymphs, the lovely daughters of the sea god Poseidon.

The sea nymphs had heard of Cassiopeia’s boast and complained to their father. Poseidon, like any father, was angered, and being a god was able to do something about. Being a god means never having to say your sorry when you do something really mean. He loosed the monster Cetus upon the Ethiopians.

The oracle said that to appease the monster and Poseidon Cassiopeia would have to sacrifice her daughter the Princess Andromeda to the monster. That is how young Andromeda was chained to the rocks on the sea shore to await her doom…

Far away in ancient Greece a wedding was about to take place between the beautiful Princess Danaë and King Polydectes. Danaë’s son Perseus, fathered by Zeus, but that’s another story, wasn’t too happy about the proposed union, and Polydectes wanted the boy gone.

When Perseus asked Polydectes what he wanted for a wedding gift, he said, “I want the head of Medusa.” The boy immediately and foolhardedly agreed to get it for him.

Merdusa, it turns out, was one of three sisters, the Gorgons, who had snakes for hair. They were so ugly that one glimpse of them would turn the beholder to stone. Medusa was the only mortal one.

Luckily Perseus had the favor of the god Hermes and Athene. They armed him with Hermes’ winged sandals, a helmet that made him invisible, a pouch that would expand to hold an object of any size, a shiny mirror shield, and a sword.

Thus armed Perseus was told to find the Graiae or the gray women, who could tell him where the lair of the Gorgons was. They were three in number and shared but one eye and one tooth among them which they passed from one to another to use.

The Graiae refused to help Perseus. But he was able to force them to help by snatching their one eye while it was being passed from one to another. They told him that the Gorgons dwelt in the shore of the river Ocean at the edge of the world in perpetual twilight.

In approaching the lair of the Gorgons Perseus put on the helmet of invisibility. He approached Medusa stepping backwards, cautiously peering only at Medusa’s indistinct image in his shield. Perseus then swept his sword in a backhanded way and managed to sever Medusa’s head. It is said that Athene guided his hand.

Amazingly, springing full grown from Medusa’s blood was the winged white stallion Pegasus. After placing Medusa’s head in the pouch, Perseus mounted Pegasus for the trip home.

Cruising high in the sky over the Ethiopian coast Perseus spotted a horrific sight. There far below the beautiful Andromeda, in chains; her screams reaching his ears. Then he spotted why she was screaming. A short distance away, crawling out of the surf was the monster Cetus, heading towards Andromeda. Perseus immediately sizes up the situations and swooped with Pegasus down to a spot between Andromeda and the monster. Then, burying his head in his shoulder drew out the head of Medusa from the pouch and held it in front of Cetus. The head was as lethal in death as in life, and the monster was promptly turned to stone. Replacing the head in the pouch, Perseus freed Andromeda. They flew off to, well supposedly, live happily ever after.

Oh yes. Perseus did present the head of Medusa to his step father Polydectes. He, of course, was also turned to stone when he laid eyes on it.

There you have it a story connecting the autumn constellations of Cepheus, Cassiopeia, Andromeda, Perseus, Pegasus and Cetus.

Cepheus is a dim church steeple of a constellation. Its dim star Delta is a variable star, the prototype of an important class of distance measuring stars called Cephieds in its honor. Cassiopeia is the famous W shaped constellation that along with Cepheus doesn’t set at our latitude.

Perseus looks to me more like the cartoon roadrunner than a hero. As the ancients saw him, he is holding the head of Medusa, whose still glittering eye is the star Algol, a variable star which ghastly winks at us every 2 days and 21 hours.

Andromeda’s modern claim to fame is the great galaxy that lies beyond her stars, the Great Andromeda Galaxy which has the designation M31. The galaxy is faintly visible to the unaided eye on dark nights. The farthest you can see without optical aid. The galaxy lies some 2.5 million light years away.

Pegasus can be easily found by the square of stars the form his body. It’s called the Great Square of Pegasus.

What can be said about Cetus. It now represents a whale, not a monster. Its star Mira, which means “Wonderful”, slowly varies in brightness over 330 days from a star barely visible in binoculars to a 2nd or 3rd magnitude star.

Look up on an autumn evening and recapture the wonder the ancients had as they looked upward at the stars.