Archive

Posts Tagged ‘Big Dipper’

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.

03/24/2017 – Ephemeris – Finding Leo

March 24, 2017 Comments off

Ephemeris for Friday, March 24th.  The Sun will rise at 7:37.  It’ll be up for 12 hours and 22 minutes, setting at 8:00.  The Moon, 3 days before new, will rise at 6:24 tomorrow morning.

At 10 p.m. the spring constellation of Leo the lion will be high in the east-southeast.  It can be found by locating the Big Dipper high in the northeast and imagining that a hole were drilled in 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 sparser than those in the winter sky.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Add info on Mercury in the evening sky.

Addendum

Leaky Dipper drips on Leo.

Leaky Big Dipper drips on Leo. Created using mu LookingUp program.

Ursa Major and Leo

Ursa Major with the Big Dipper in her hind end and Leo. Created using Stellarium and GIMP.

02/20/2017 – Ephemeris – The spring constellations are rising

February 20, 2017 Comments off

Ephemeris for President’s Day, Monday, February 20th.  The Sun will rise at 7:34.  It’ll be up for 10 hours and 44 minutes, setting at 6:18.  The Moon, 2 days past last quarter, will rise at 3:59 tomorrow morning.

With spring only a month away, lets turn our eyes eastward in the evening to the rising spring stars.  In contrast to the brilliant stars of the winter skies still holding forth in the south, and running along the Milky Way overhead and to the northwest, the stars to the east are rather sparse and dull.  The only exception is the Big Dipper to the northeast.  The one bright star in the east is Regulus, whose rank as a first magnitude star is dead last in brightness.  It is in the heart of the constellation of Leo the lion, and as such has gained a great amount of fame.  Regulus is at the base of a backward question mark of stars that is informally known a the Sickle.  It is also the characteristic head and mane of a male lion.  A triangle of stars to the lower left are his back end ending with Leo’s second brightest star Denebola, literally “Lion’s Tail”.

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

Addendum

 

Comparison of winter stars vs. spring stars.

Comparison of winter stars vs. spring stars. Created using Stellarium.

The constellation Leo animation

The constellation Leo animation. Created using Stellarium and GIMP.

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.

05/27/2016 – Ephemeris – Alkaid, the star at the end of the Big Dipper

May 27, 2016 Comments off

Ephemeris for Friday, May 27th.  Today the Sun will be up for 15 hours and 14 minutes, setting at 9:17, and will rise tomorrow at 6:02.   The Moon, 2 days before last quarter, will rise at 1:40 tomorrow morning.

The star at the end of the handle of the Big Dipper is named Alkaid.  It is the bright star that’s closest to the zenith at 11 p.m.  It is a rare blue-white star.  Alkaid and Dubhe, at the other end of the Big Dipper are stars that do not belong to the Ursa Major Association.  And thousands of years from now these two stars will leave the central stars of the dipper behind, and deform the Big Dipper.  Over the millennia the Big Dipper would look like a tin cup.  Near Alkaid are two popular deep sky objects.  And being this far from the hazy band of the Milky Way one would guess that they would be galaxies.  And they are. The Whirlpool Galaxy and the Pinwheel Galaxy.  Two gorgeous spiral galaxies.

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

Addendum

The change in the Big Dipper over time.

The change in the Big Dipper over time. Source: stargazerslounge.com.  Ultimate source:  Stellarium.

Alkaid and the Big Dipper

The Big Dipper and Alkaid with the Whirlpool (M51) and Pinwheel (M101) galaxies. Created using Stellarium.

M51

The Whirlpool Galaxy, M51. Credit Scott Anttila.

M101

The Pinwheel Galaxy, M101. Credit Scott Anttila.

05/26/2016 – Ephemeris – Polaris the North Star

May 26, 2016 Comments off

Ephemeris for Thursday, May 26th.  Today the Sun will be up for 15 hours and 12 minutes, setting at 9:16, and will rise tomorrow at 6:03.   The Moon, 3 days before last quarter, will rise at 1:02 tomorrow morning.

The star Polaris is perhaps the most important star in the northern hemisphere sky.  That’s because it is nearly over the Earth’s north pole.  It’s also called the North Star or the Pole Star.  Polaris can be found by using the two stars at the front of the bowl of the Big Dipper,  These two stars, we call Pointer Stars do point very accurately to Polaris.  It is not the brightest star as some think, but a brighter than average star in a most unique position in the sky.  During the lifetimes of those now living Polaris will be getting slowly closer to the pole.  It won’t reach it, but in 100 years will begin to recede from the pole.  The altitude of Polaris in degrees approximately equals ones latitude.

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

Addendum

How to fing Polaris

Looking North at the Big Dipper pointing at Polaris. Created using my Looking Up program.

Polaris and the pole

Closeup of Polaris and the Celestial North Pole. The declination lines are 1 degree apart. Created using Cartes du Ciel (Sky Charts).

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.