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Posts Tagged ‘Arcturus’

05/14/2018 – Ephemeris – Big Dipper: Pointer to the Stars

May 14, 2018 Comments off

Ephemeris for Monday, May 14th. Today the Sun will be up for 14 hours and 47 minutes, setting at 9:03, and it will rise tomorrow at 6:14. The Moon, 1 day before new, will rise at 6:45 tomorrow morning.

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

Addendum

As can be seen below, there was one pointer function that didn’t make it into the program:  A leaky dipper drips on Leo.

Big Dipper Pointer to the Stars

Using the Big Dipper as a pointer to other stars. The pointers to Polaris could be life saving, since it is always north. The view is southward. The cross displayed near the center is the zenith. One might want to lay down to take all this in. Created using my LookingUp program.

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04/09/2018 – Ephemeris – Follow the arc to Arcturus

April 9, 2018 Comments off

Ephemeris for Monday, April 9th. The Sun will rise at 7:09. It’ll be up for 13 hours and 11 minutes, setting at 8:20. The Moon, 1 day past last quarter, will rise at 4:40 tomorrow morning.

The fourth brightest night-time star is now up in the east. 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 remembering the line “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 times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Arc to Arcturus

Look high in the east on a spring evening to follow the arc of the Big Dipper’s handle to Arcturus. Created using Stellarium ans GIMP.

Categories: stars Tags: ,

06/27/2017 – Ephemeris – Arcturus as a look at the Sun’s future

June 27, 2017 1 comment

Ephemeris for Tuesday, June 27th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:31, and it will rise tomorrow at 5:59. The Moon, 3 days before first quarter, will set at 12:18 tomorrow morning.

With the Moon brightening the night sky, let’s take a look at the star Arcturus, which with its pointer, the curve of the Big Dipper’s handle is slipping into the high western sky. Arcturus is the 4th brightest night time star, though some think the star Vega, high in the east is brighter. They are different colors because Arcturus is orange, while Vega is whiter than the Sun. Arcturus is a preview of what the Sun will become in four or five billion years from now. It is only 10% more massive than the Sun and is that much older than the Sun, so it is turning into its red giant stage, after running out of hydrogen to turn into helium in its core to produce energy. The helium is now compressing and heating to begin its reaction.

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

Addendum

Arcturus finder chart

Arcturus finder chart with the Big Dipper and Vega as guide posts. Created using Stellarium.

Here’s one of my prior posts about Arcturus, about its great space velocity:  https://bobmoler.wordpress.com/2016/04/26/04262016-ephemeris-arcturus-just-passing-through/

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.