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Posts Tagged ‘Arcturus’

06/28/2022 – Ephemeris – Finding the celestial harp

June 28, 2022 Leave a comment

This is Ephemeris for Tuesday, June 28th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon is new today, and won’t be visible.

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 4th or 5th brightest nighttime star*, and currently the topmost star of the Summer Triangle. 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 are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

*Vega’s rival for the fourth spot on the brightness list is Arcturus to it’s west. Wikipedia’s source says that Arcturus is slightly brighter. Stellarium’s source says Vega is brighter. The difference is a few hundredths of a magnitude. However, they are of different colors. Vega is pure white, while Arcturus is yellow-orange because it has a cooler surface temperature than Vega. Check them out for yourself.

Addendum

Annimated Lyra finder chart

Animated Lyra finder chart. The lyre image not supplied by Stellarium but is from The World’s Earliest Music by Hermann Smith, Figure 60, A Project Gutenberg E-Book, and captioned “The Chelys or Greek Tortoiseshell Lyre”. The three names stars are the stars of the Summer Triangle in the eastern sky these evenings of late June. Created using Stellarium.

04/28/2022 – Ephemeris – The story of Arcas and Callisto

April 28, 2022 Comments off

This is Bob Moler with Ephemeris for Thursday, April 28th. Today the Sun will be up for 14 hours and 6 minutes, setting at 8:44, and it will rise tomorrow at 6:35. The Moon, 2 days before new, will rise at 6:16 tomorrow morning.

Appearing in the eastern sky at 10 p.m. tonight is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom of the kite which is horizontal to the left, pointed to by the arc of the handle of the Big Dipper, higher in the east. The Big Dipper is the hind end of the constellation Ursa Major, the Great Bear. In one story, Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young woman who had the misfortune of being loved by god Zeus. Zeus’ wife, Hera, found out about the affair, and since she couldn’t punish Zeus, turned the poor woman into a bear. Arcas, many years later, unaware of why his mother disappeared, was about to kill the bear when Zeus intervened and placed them both in the sky, where he continues to chase 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

Arcas and Callisto

Boötes and Ursa Major aka Arcas chasing Callisto around the pole of the sky. Created using Stellarium.

Arcas and Callisto woodcut

Arcas about to slay the bear by the 17th century artist Baur. Source: University of Virginia Electronic Text Center

04/18/2022 – Ephemeris – Arcturus, the fourth-brightest nighttime star*

April 18, 2022 Comments off

This is Ephemeris for Monday, April 18th. Today the Sun will be up for 13 hours and 38 minutes, setting at 8:31, and it will rise tomorrow at 6:51. The Moon, 2 days past full, will rise at 11:17 this evening.

The fourth-brightest nighttime star* is now up in the east these evenings. It is Arcturus, a bright star with an orange hue. It can be found otherwise by finding the Big Dipper and tracing out and extending the curve of the handle and saying the phrase “Follow the arc of the handle to Arcturus”, to remember the name of the star and how to find it. Arcturus is about 37 light years from us and is moving quite rapidly across the sky, compared to most stars, but one would not notice it to the naked eye in one’s lifetime. Arcturus is slightly more massive than our Sun, and about 7 billion years old, and is entering its red giant stage of life after using all the hydrogen fuel in its core. Our Sun, being slightly less massive, will survive on hydrogen a bit longer.

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.

*Or 5th brightest star, depending on which list you look at. Arcturus and Vega, which is just above the horizon in the northeast at 10 pm, are nearly the same brightness, however Vega is white while Arcturus is orange, making brightness comparisons difficult visually. Stellarium, however, reports Vega is a slightly brighter magnitude 0.00, while Arcturus is 0.15. My older lists say Arcturus is the 4th brightest star. I’m an older guy, so I’m sticking with it.

Addendum

How to find Arcturus nearly a month into spring. Arcturus is in the east in the evening. The Big Dipper is high in the northeast standing on its handle. To find and remember the name of this star, simply follow the arc of the handle to Arcturus. Created using Stellarium and GIMP.

I’ll have more tidbits about this remarkable star throughout the spring and summer. Can’t wait? Search for Arcturus on this blog.

06/03/2021 – Ephemeris – Arcturus in the Bible.

June 3, 2021 Comments off

This is Ephemeris for Thursday, June 3rd. Today the Sun will be up for 15 hours and 23 minutes, setting at 9:23, and it will rise tomorrow at 5:58. The Moon, 1 day past last quarter, will rise at 3:30 tomorrow morning.

Arcturus is a bright orangish star that’s high in the south at 11 pm. It’s also found by following the arc of the handle of the Big Dipper, which is the ridiculous tail of Ursa Major the Great Bear. It was considered the “Guardian of the Bear”, It is in the base of the kite shaped constellation of Boötes, the herdsman or the Bear Chaser. The latter story I recounted earlier this year. The name from the Greek has been confused with the bear itself. Thus, in the King James version of the Bible Arcturus, not the Bear, meaning the Great Bear, is mentioned in the 38th chapter of Job. This has been corrected in the newer versions I’ve seen. Arcturus has a rich history in literature, mostly by being confused with the Great Bear.

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

Addendum

Arcturus, Bootes and Ursa Major

Arcturus, Boötes and Ursa Major can be seen by looking overhead while facing the west-southwest at 11 pm in early June. Created using Stellarium. Lines and figures not included.

Biblical translations

King James Version of Job 38:31-32

31 Canst thou bind the sweet influences of Pleiades, 
   or loose the bands of Orion?

32 Canst thou bring forth Mazzaroth in his season?
   or canst thou guide Arcturus with his sons?

New International Version of Job 38:31-32

31 
“Can you bind the chains of the Pleiades?
Can you loosen Orion’s belt?
32 
Can you bring forth the constellations in their seasons
or lead out the Bear with its cubs?

No one is sure what a Mazzaroth is.

04/09/2021 – Ephemeris – Follow the arc to Arcturus

April 9, 2021 Comments off

This is Bob Moler with Ephemeris for Friday, April 9th. Today the Sun will be up for 13 hours and 12 minutes, setting at 8:20, and it will rise tomorrow at 7:06. The Moon, 2 days before new, will rise at 6:57 tomorrow morning.

The fourth or fifth brightest night-time star, depending on whose list you see, is now up in the east in the evening. It is Arcturus, a bright star with an orange hue. It can be found otherwise by finding the Big Dipper and tracing out and extending the curve of the handle and “Follow the arc of the handle to Arcturus”, to remember the name of the star and how to find it. Arcturus is about 37 light years from us and is moving quite rapidly across the sky, compared to most stars, though one would not notice it to the naked eye in one’s lifetime. Arcturus is slightly more massive than our Sun, and about 7 billion years old, and is entering its red giant stage of life after using all the hydrogen fuel in its core. Our Sun, being slightly less massive will survive on hydrogen a bit longer.

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

Addendum

How to find Arcturus
How to find Arcturus. In the early spring Arcturus is low in the east in the evening. The Big Dipper is high in the northeast standing on its handle. To find and remember the name of this star simply follow the arc of the handle to Arcturus. Created using Stellarium and GIMP.

I’ll be talking more about Arcturus and the constellation it’s in Boötes the herdsman, a kite shaped constellation that’s currently laying on its side. He’s not herding, but chasing the Great Bear. But that’s another story.

03/11/2021 – Ephemeris – The Guardian of the Bear is rising

March 11, 2021 Comments off

This is Ephemeris for Thursday, March 11th. Today the Sun will be up for 11 hours and 42 minutes, setting at 6:44, and it will rise tomorrow at 7:00. The Moon, 2 days before new, will rise at 7:09 tomorrow morning.

The brightest star of spring is Arcturus which will be visible by 9 pm low in the east-northeast. Arcturus can most famously be found by following the arc of the handle of the Big Dipper, which resides fairly high in the northeastern sky to it. “Follow the arc of the handle to Arcturus.” It’s the fourth or fifth brightest star in the sky, depending on the list. It was regarded as the “Guardian of the Bear”, meaning the Great Bear, Ursa Major, of which the Big Dipper is its hind end. Apparently it’s guarding its rear. Arcturus will stay in our evening sky until the end of summer and has a fascinating story of its own aside from its ancient mythology, which I’ll talk about when it’s higher in the sky. It’s located at the base of a kite shaped constellation called Boötes, which is now horizontal and too close to the horizon to be appreciated.

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

Addendum

Arcturus rising finder animation

Arcturus rising finder animation for 9 pm tonight, March 11, 2021. Created using Stellarium and GIMP.

06/25/2020 – Ephemeris – The bright star Spica

June 25, 2020 Comments off

This is Ephemeris for Thursday, June 25th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 3 days before first quarter, will set at 12:59 tomorrow morning.

Low in the southwest at 11 p.m. is the bright star Spica which can be found from all the way back overhead to the Big Dipper. Follow the arc of the handle of the Big Dipper to the bright star Arcturus high in the southwest. Then straighten the curve of the arc to a straight spike which points to Spica. Arcturus is much brighter than Spica and has an orange tint to Spica’s bluish hue. In fact Spica is the bluest of the 21 first magnitude stars. That means that it is hot. Actually Spica is really two blue stars orbiting each other in 4 days. Spica is 250 light years away, which is reasonably close. Spica was an important star to the ancient Greeks. One temple was built, and aligned to its setting point.

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

Addendum

Spica finder chart

Spica finder chart using my LookingUp program fo 11 p.m. tonight June 25.

06/23/2020 – Ephemeris – Arcturus: a look at the Sun’s future

June 23, 2020 Comments off

This is Ephemeris for Tuesday, June 23rd. 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, 2 days past new, will set at 11:49 this evening.

Arcturus, a red giant star is about two thirds the way up the sky in the southwest at 11 p.m. It’s one of the earliest stars to appear in twilight, being nearly tied in brightness with Vega, a white star nearly as high in the east. A pointer to Arcturus is the handle of the Big Dipper, following the arc of the handle to Arcturus. Though only 37 light years away, it’s not from around here. It’s passing through the galactic disk from north to south. Arcturus is about 7 billion years old, and is about 8% more massive than our Sun. It appears to be starting its red giant phase, after running out of hydrogen to fuse to helium in its core and is beginning to fuse helium. It’s a preview of coming attractions for our Sun when it gets that old.

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

Addendum

Arcturus finder diagram

Arcturus is easy to find. It’s the brightest star in the southwest in the evening. This is 11 pm tonight June 23, 2020. Note the Big Dipper and its handle to the upper right. Created using Stellarium.

05/15/2020 – Ephemeris – Virgo and its cluster of galaxies

May 15, 2020 Comments off

This is Ephemeris for Friday, May 15th. Today the Sun will be up for 14 hours and 50 minutes, setting at 9:04, and it will rise tomorrow at 6:12. The Moon, 1 day past last quarter, will rise at 4:01 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, the 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 that was imaged last year. The center of the cluster is at about 54 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

Finding Spica

Spica finder animation . Click on the image to enlarge. Created using Stellarium and GIMP.

Virgo Cluster

Some of the brighter members of the Virgo Cluster (of galaxies) as red ovals. The galaxies marked with an ‘M’ number are part of Charles Messier’s catalog. It took a telescope of 8 inch diameter for me to spot them. Someone with better vision, like Messier himself can spot them with a smaller telescope. M53 and the object next to it are globular star clusters in the outer reaches of our galaxy. Created using Cartes du Ciel (Sky Charts).

Markarian Chain of galaxies

Markarian Chain of galaxies within the Virgo Cluster by Scott Anttila.

Black hole in M87

The first image of the black hole in M87. Credit Event Horizon Telescope.

 

 

04/24/2020 – Ephemeris – The Big Dipper can be used to point to other stars and constellations

April 24, 2020 Comments off

This is Bob Moler with Ephemeris for Arbor Day, Friday, April 24th. Today the Sun will be up for 13 hours and 57 minutes, setting at 8:39, and it will rise tomorrow at 6:41. The Moon, 2 days past new, will set at 10:21 this evening.

The Big Dipper can be used to point to other stars and constellations. Right now the Big Dipper is nearly overhead. The front bowl stars point to Polaris, the North Star which never seems to move in the sky. The handle can be used to find two stars. First follow the arc of the handle away from the bowl to find the fourth brightest night-time star Arcturus in the base of the kite shaped constellation of Boötes. Straighten the arc to a spike and continue to the south and you will come to the bright blue-white star Spica in Virgo the virgin. You can remember these stars with the phrase “Follow the arc of the handle to Arcturus and then spike to Spica” or if you prefer the alternate pronunciation of the latter star “Speak to Speeka”.

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

Addendum

Finding stars and constellations using the Big Dipper

Finding stars and constellations using the Big Dipper. Click on the image to enlarge. Created using my LookingUp program for Windows.