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Posts Tagged ‘Arcturus’

04/24/2017 – Ephemeris – A story of the Great Bear, Ursa Major

April 24, 2017 Comments off

Ephemeris for Monday, April 24th.  The Sun rises at 6:42.  It’ll be up for 13 hours and 55 minutes, setting at 8:38.  The Moon, 2 days before new, will rise at 6:32 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 to the right, pointed to by the arc of the handle of the Big Dipper, higher in the east.  In one story 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 the affair, and since she couldn’t punish Zeus, turned the poor woman into an ugly bear.  Arcas, many years later, unaware of the events surrounding his mother’s disappearance was about to kill the bear when Zeus intervened and placed them both in the sky to save her, as he continues to chase her across the sky nightly.

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

Addendum

Arcas and Callisto

Bootes 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

04/17/2017 – Ephemeris – How to find the stars Arcturus and Spica from the Big Dipper

April 17, 2017 Comments off

Ephemeris for Monday, April 17th.  The Sun rises at 6:54.  It’ll be up for 13 hours and 35 minutes, setting at 8:30.  The Moon, 2 days before last quarter, will rise at 2:21 tomorrow morning.

The Big Dipper, now nearing the zenith at 10 p.m. 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 night-time star.  The reason I say night-time is that the sun is a star also but by definition is not out at night.  The arc to Arcturus is a how to find Arcturus and a clue to its name.  Arcturus, midway up the sky in the east, 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 low in the southeast.  It is below Jupiter this year.  Spica is also sometimes pronounced ‘Speeka’.

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

Addendum

Finding Arcturus and Spica

How to find the stars Arcturus and Spica from the Big Dipper in April 2017. Created using my LookingUp program.

06/09/2016 – Ephemeris – Waiting for the first stars to appear

June 9, 2016 Comments off

Ephemeris for Thursday, June 9th.  Today the Sun will be up for 15 hours and 30 minutes, setting at 9:27, and it will rise tomorrow at 5:56.  The Moon, 3 days before first quarter, will set at 12:59 tomorrow morning.

Lets look at the first stars and planets to appear tonight as it gets dark.  The first object to appear will be the fat crescent Moon in the southwest.  The planet Jupiter will be the next to appear after sunset left and above the Moon.  Mars, low in the southeast will appear reddish, shortly thereafter.  Looking very high in the southeast, the fourth brightest nighttime star will appear.  This will be Arcturus with an orange hue.  Saturn should appear to the left and below Mars.  Soon other stars will appear including the Big Dipper overhead.  Other bright stars will appear, the summer star Vega low in the northeast. Regulus between Jupiter and the Moon and Spica between Jupiter and Mars.

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

Addendum

The first stars and planets to appear after sunset

The sky at about 10 p.m. or a little later, watching the first stars and planets appear. Created using Stellarium. If viewing using Firefox right-click on the image and select View Image to enlarge.

05/24/2016 – Ephemeris – Follow the spike to Spica

May 24, 2016 Comments off

Ephemeris for Tuesday, May 24th.  Today the Sun will be up for 15 hours and 9 minutes, setting at 9:14, and will rise tomorrow at 6:04.  The Moon, 3 days past full, will rise at 11:35 this evening.

Just about due south 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 south, southeast.  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 ancients.  One temple was built, and aligned to its setting point.

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

Addendum

Spike to Spica

The evening sky to the south. All the finder stars are there, so follow the arc of the Big Dipper’s handle to Arcturus. Straighten it to a spike that points to Spica. Created using Stellarium.

04/26/2016 – Ephemeris – Arcturus, just passing through

April 26, 2016 Comments off

Ephemeris for Tuesday, April 26th.  The Sun rises at 6:39.  It’ll be up for 14 hours and 2 minutes, setting at 8:42.   The Moon, 3 days before last quarter, will rise at 12:48 tomorrow morning.

Arcturus is an orange-colored giant star, 37 light years away.  We see it high in the east and pointed to by following the arc of the handle of the Big Dipper.  Arcturus is a rapidly moving star.  It’s velocity is about 76 miles per second (122 km/s).  It’s almost at its nearest to the Sun now.  In the next 2,000 years it will move about one degree, twice the width of the Moon toward Spica.  Arcturus may be part of a dwarf galaxy being assimilated by the Milky Way which may account to its odd motion.  Arcturus is thought to be close to 8% more massive than the Sun and about 6 to 8 ½ billion years old.  It has entered its red giant stage after running out of hydrogen in its core.  It may be a glimpse of what the sun will look like in 5 billion years.

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

Addendum

Arcturus in motion.

The constellation Bootes and the 4th brightest star in the night sky. The thin line extending to the right from Arcturus is the distance it will travel in the next 2,000 years. That line is nearly one degree ling, or 2 Mon diameters. Created using Cartes du Ciel (Sky Charts)

Categories: Ephemeris Program, stars Tags:

03/28/2016 – Ephemeris – The brightest spring star is now rising in the east

March 28, 2016 Comments off

Ephemeris for Monday, March 28th.  The Sun will rise at 7:30.  It’ll be up for 12 hours and 35 minutes, setting at 8:06.   The Moon, 3 days before last quarter, will rise at 1:07 tomorrow morning.

Rising in the eastern sky at 10 p.m. is the 4th brightest night-time star.  It’s found off the curve of the handle of the Big Dipper above it in the northeast. It’s the tail end of a kite shaped constellation of Boötes the herdsman.   Arcturus is an orange-colored giant star, 37 light years away.  Its light was used open the 1933 Chicago Worlds Fair believing its light left the star in 1893 the year of the previous Chicago Worlds Fair.  It turns out that Arcturus is 3 light years closer than what they thought.  Arcturus is a rapidly moving star.  It’s velocity is about 76 miles (122 km) per second. It’s at its nearest to the sun now.  Arcturus is thought to be close to the sun’s mass, and much older.  It may be a glimpse of what the sun will look like in 5 billion years.

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

Addendum

Arcturus finder chart

Arcturus off the handle of the Big Dipper rising. Created using Stellarium.

07/09/2015 – Ephemeris – The first stars to appear at night

July 9, 2015 Comments off

Ephemeris for Thursday, July 9th.  Today the Sun will be up for 15 hours and 23 minutes, setting at 9:29.   The Moon, 1 day past last quarter, will rise at 2:05 tomorrow morning, and tomorrow the Sun will rise at 6:07.

Let’s check out all the bright stars in the evening sky, as it gets dark tonight.  Low in the west are the planets Venus and Jupiter.  High in the west is the bright yellow-orange star Arcturus.  In the northwest is the Big Dipper,  whose curved handle points to Arcturus.  Straightening that curve to a spike will point to Spica a blue-white star low in the southwest.  The planet Saturn is located in the south.  Below and left of it is the red star Antares which usually twinkles merrily.  High in the east is the bright white star Vega.  To its lower right is Altair, and to its lower left the star Deneb.  Vega, Altair and Deneb make the Summer Triangle, whose rising in the east signals the coming of summer.

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

Addendum

I talked about seeing the first stars a month ago.  It seems that in holding star parties this time of year we spend a lot of time watching the first stars appear.  I wanted to discuss the Summer Triangle, but it wandered off to what you see above.  I’ll get there next week, I promise.

Firsat stars to appear

The first stars and planets to appear. See if you can located them from the text. Created using Stellarium for about 10 p.m., July 9, 2015.