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Posts Tagged ‘Cygnus’

07/14/2017 – Ephemeris – Constellations of the Summer Triangle II: Cygnus the swan

July 14, 2017 1 comment

Ephemeris for Friday, July 14th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:25, and it will rise tomorrow at 6:11. The Moon, 2 days before last quarter, will rise at 12:32 tomorrow morning.

Fairly high in the east at 11 p.m. Is the constellation of Cygnus the swan, flying south through the Milky Way. It is also called the Northern Cross. At the left, the tail of the swan or the head of the cross is the bright star Deneb, one of the stars of the Summer Triangle. The next star right is Sadr the intersection of the body and the wings of the swan seen in flight, or the intersection of the two pieces of the cross. There are two or three stars farther to the right that delineate the swan’s long neck or upright of the cross, that ends with the star Alberio in the beak of the swan or foot of the cross. The crosspiece of the cross extends to the stars on either side of the intersection star Sadr, while the swan’s wings extend to a couple more stars each.

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

Addendum

The Summer Triangle July 5, 2012 at 11 p.m. Created using Stellaruim and The Gimp.

The Summer Triangle. Created using Stellarium and The Gimp.

Cygnus finder animation

Animated Cygnus finder chart. Created using Stellarium.

In mythology Cygnus was the form Zeus took in the Leda and the swan affair.  Out of that union was born Pollux of Gemini fame.  His half-brother and twin Castor was fathered by a mere mortal.  Go here for their story.

Alberio is the star that shows in Cygnus’ eye.  In telescopes of even low power Alberio shows as a binary star whose components are distinctly and beautiful blue and gold.  Binoculars are not quite powerful enough to split these two.

07/10/2017 – Ephemeris – Deneb, a super bright star

July 10, 2017 1 comment

Ephemeris for Monday, July 10th. Today the Sun will be up for 15 hours and 20 minutes, setting at 9:27, and it will rise tomorrow at 6:08. The Moon, 1 day past full, will rise at 10:24 this evening.

This evening when it gets dark the bright star Deneb in Cygnus the swan will be high in the east-northeast. Deneb is the dimmest star of the summer triangle. Of the other stars of the triangle, Vega is higher in the east, while Altair is lower in the southeast. While Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars, Deneb’s vast distance of possibly 1,400 light years* makes it over 50 times the distance of Vega. If brought as close as Vega, Deneb would be as bright at least as the quarter moon. It is possibly as bright as 200 thousand Suns; and a huge star, possibly as large in diameter as the orbit of the Earth. For all this it is only 20 to 25 times the mass of the sun.

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

* Deneb’s distance is not well known.  Over the years with the Ephemeris program and this blog I’ve given various distances to the star.  Having no companion and being beyond the distance where trigonometric parallax is used, at least from the ground, makes distance measurement difficult.  Hipparcos  satellite measurements give a distance about twice as great.  Estimates of the true brightness of a star are based on its known distance.  An error in distance by a factor of two gives an error in terms of intrinsic luminosity by a factor of 4, due to the inverse square law of brightness with distance.

Addendum

The constellations Lyra, Cygnus and Aquila

Deneb with the other stars and constellations in the Summer Triangle. Created using Stellarium.

Deneb & North American Nebula

One of my old photographs of Deneb and the North American Nebula digitized from a slide. Deneb’s ultraviolet emissions cause the North American and unnamed here Pelican Nebulae to glow.  The red color is due to hydrogen.

06/22/2017 – Ephemeris – Now that it’s summer, lets check out the Summer Triangle

June 22, 2017 1 comment

Ephemeris for Thursday, June 22nd. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 1 day before new, will rise at 5:45 tomorrow morning.

We’re a day into summer, and the asterism or informal constellation called the Summer Triangle can be seen rising in the east as it gets dark. Highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram nearby. The second star of the triangle is Deneb lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years while Deneb may be a whopping 2600 light years away. One light year is 6 trillion miles (9 trillion km).

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

Addendum

The Summer Triangle July 5, 2012 at 11 p.m. Created using Stellaruim and The Gimp.

The Summer Triangle. Created using Stellarium and The Gimp.

01/13/2017 – Ephemeris – Perhaps we’ll see a nova in 5 years, 2022

January 13, 2017 Comments off

Jan 13.  This is Bob Moler with Ephemeris for Friday, January 13th.  The Sun will rise at 8:16.  It’ll be up for 9 hours and 9 minutes, setting at 5:26.  The Moon, 1 day past full, will rise at 7:12 this evening.

Professor Larry Molnar from Calvin College in my home town of Grand Rapids and his students discovered that a star, [KIC 9832227,] that was monitored by the Kepler exoplanet finding satellite in the northern constellation of Cygnus the Swan may explode in about 5 years.  The star is actually two so close that they share their outer atmospheres, someone described it as two peanuts in one shell.  The two orbit each other in 11 hours now, and the period is shortening at an accelerated rate as the two approach each other.  Astronomers think that it will repeat the fate of a star that exploded in 2008 in the constellation of Scorpius.  Such explosions, when seen are called Novae.  A Nova like this could make the star briefly 10,000 times brighter than it originally was. [Current magnitude is 12, which is visible in moderate sized (6″ or 150 mm) diameter telescopes.  10,000 times brighter equals a 10 magnitude bump, which would make the star 2nd magnitude.  Magnitudes are like golf scores the lower the magnitude the brighter the object.  Blame Hipparchus.]

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

Note:  The text in brackets omitted in the broadcast.

Addendum

 

Finder Chart

Finder Chart for KIC 9832227. It’s in the red bulls eye. Credit: Calvin College.

The position of KIC 9832227 is circumpolar or nearly so for northern Michigan.  So it’s up all or most of the 24 hour day, so no matter the time of year this baby blows, we should be able to see it.

What the star(s) may look like

Two computer generated views of KIC 9832227. The large star is about twice the Sun’s diameter, while the smaller star is a bit less than the Sun’s size. Credit: Calvin College.

For more information click here:  https://calvin.edu/news/archive/astronomy-prof-student-predict-explosion-that-will-change-the-night-sky.

10/03/2016 – Ephemeris – Cassiopeia the celestial queen, and a look at Venus with the Moon

October 3, 2016 Comments off

Ephemeris for Monday, October 3rd.  The Sun will rise at 7:43.  It’ll be up for 11 hours and 34 minutes, setting at 7:18.  The Moon, 3 days past new, will set at 8:55 this evening.

The stars of autumn are in the northeastern to southeastern part of the evening sky.  Look half way up the sky in the northeast at 9 p.m. and you can find the W shaped constellation of Cassiopeia the queen.  Cassiopeia never sets for us in Michigan.  It is opposite the pole star Polaris from the Big Dipper.    Above Cassiopeia is a dim church steeple shaped constellation of Cepheus the king.  The steeple is toppled to the left.  The Milky Way flows through Cassiopeia and through a corner of Cepheus to the bright star Deneb in Cygnus the Swan, or Northern Cross, overhead. Below Cassiopeia it flows through the constellation of Perseus the hero, which kind of looks like a chicken, to the bright star Capella near the horizon.

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

Addendum

The crescent Moon will appear above Venus tonight.

Venus and the Moon

Looking very low in the west-southwest at 7:38 p.m., 20 minutes after sunset, October 3, 2016. The thin crescent Moon will appear about 4 degrees 15 minutes (8 1/2 moon diameters) above Venus. Created using Stellarium.

Cassiopeia and the Milky Way

Cassiopeia with Cepheus, Cygnus and Perseus in the Milky Way in the northeastern sky. Created using Stellarium.

07/29/2016 – Ephemeris – Aquila the Eagle, third constellation of the Summer Triangle

July 29, 2016 Comments off

Ephemeris for Friday, July 29th.  The Sun rises at 6:26.  It’ll be up for 14 hours and 45 minutes, setting at 9:11.  The Moon, 3 days past last quarter, will rise at 3:20 tomorrow morning.

Aquila the eagle is a constellation that lies in the Milky Way.  It’s in the southeastern sky as it gets dark.  Its brightest star, Altair is one of the stars of the Summer Triangle, a group of three bright stars seen now in the eastern sky in the evening.  Altair, in the head of the eagle, is flanked by two slightly dimmer stars, the shoulders of the eagle.  The eagle is flying northeastward through the Milky Way.  Its wings are seen in the wing tip stars. A curved group of stars to the lower right of Altair is its tail.  Within Aquila the Milky Way shows many dark clouds as part of the Great Rift that splits it here.  The other summer bird is Cygnus the swan, which I talked about Tuesday, above and left of Aquila, flying in the opposite direction.

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

Addendum

Aquila

Aquila the Eagle in the southeastern sky. Created using Stellarium.

 

074/26/2016 – Ephemeris – The flying swan and Northern Cross

July 26, 2016 Comments off

Ephemeris for Tuesday, July 26th.  The Sun rises at 6:22.  It’ll be up for 14 hours and 52 minutes, setting at 9:15.  The Moon, at last quarter today, will rise at 1:09 tomorrow morning.

Fairly high in the east at 11 p.m. Is the constellation of Cygnus the swan, flying south through the Milky Way.  It is also called the Northern Cross.  At the left, the tail of the swan or the head of the cross is the bright star Deneb, one of the stars of the Summer Triangle.  The next star right is Sadr the intersection of the body and the wings of the swan seen in flight, or the intersection of the two pieces of the cross.  There are two or three stars farther to the right that delineate the swan’s long neck or upright of the cross, that ends with the star Alberio in the beak of the swan or foot of the cross.  It takes a telescope, but Alberio splits into a beautiful blue and gold binary star.

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

Addendum

CygnusTheSwan Created using Stellarium.

Cygnus the Swan Created using Stellarium.