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Posts Tagged ‘Perseus’

11/09/2017 – Ephemeris – Cassiopeia the queen and her husband

November 9, 2017 1 comment

Ephemeris for Thursday, November 9th. The Sun will rise at 7:31. It’ll be up for 9 hours and 49 minutes, setting at 5:20. The Moon, 1 day before last quarter, will rise at 10:59 this evening.

The stars of the autumn skies hold forth now, but one prominent autumn constellation never leaves us, here in northern Michigan. Look high in the northeastern sky by 8 p.m. and you can find the W shaped constellation of Cassiopeia the queen. It is opposite the pole star Polaris from the Big Dipper, slinking low in the north-northwest. There’s a dim star that appears above the middle star of the W which turns the W into a very crooked backed chair. Above and left of Cassiopeia is a dim upside down church steeple shaped constellation of Cepheus the king. The Milky Way flows through a corner of Cepheus and Cassiopeia toward the northeastern horizon and through the constellation of Perseus the hero, and the bright star Capella in Auriga the Charioteer.

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

Addendum

Cassiopeia and friends

Cassiopeia and constellations along the Milky Way in the northeast these autumn evenings. (8 p.m. November 9, 2017). Click on image to enlarge. Created using Stellarium and GIMP.

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11/07/2017 – Ephemeris – The autumn constellations are all visible in the early evening

November 7, 2017 1 comment

Ephemeris for Election Day for some folks, Tuesday, November 7th. The Sun will rise at 7:28. It’ll be up for 9 hours and 54 minutes, setting at 5:23. The Moon, 3 days before last quarter, will rise at 8:49 this evening.

We’ll have about an hour and a half of reasonably dark skies between 6:30 and nearly 9 p.m. – At 8 p.m. all the autumn constellations are visible. The Zodiacal constellations from Capricornus in the southwest through Aquarius, Pisces and Aries, all relatively faint to Taurus rising in the east northeast. Pegasus the flying horse is seen in the high south-southeast. It and the connected constellation of Andromeda the chained princess are seen above Aquarius through Aries. The bright star Fomalhaut holds a lonely vigil low in the south, High in the northeast is the W shaped constellation of Cassiopeia the queen, under which is Perseus, her son-in-law and hero down to the bright star Capella.

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

Autumn constellations.

The sky at 8 p.m. November 7, 2017 showing the autumn constellations, centered on the southeastern sky. Click on the image to enlarge. The Milky Way has been brightened to show its passage through Perseus better. The red line is the ecliptic, the path of the Sun through the Zodiac. Created using Stellarium.

Addendum

 

10/30/2017 – Ephemeris – Halloween preview: The Ghoul Star

October 30, 2017 1 comment

Ephemeris for Monday, October 30th. The Sun will rise at 8:17. It’ll be up for 10 hours and 15 minutes, setting at 6:33. The Moon, 3 days past first quarter, will set at 3:50 tomorrow morning.

Tomorrow night is the spookiest night of the year, so lets preview the spookiest star of all. It’s Algol, from Ghoul Star or Demon Star. The Chinese had a name for it that meant ‘piled up corpses’. It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening. The star is located where artists have drawn the severed head of Medusa, whom he had slain. Medusa was so ugly that she turned all who gazed upon her to stone. Algol is her still glittering eye. Astronomers finally found out what was wrong with Algol. It does a slow 6 hour wink every two days 21 hours, because it is two stars that eclipse each other. It began to dip this morning just before sunrise and it will again centered on 11:41 p.m. Friday night.

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

Addendum

Algol Finder

Perseus, Cassiopeia, Andromeda with Algol finder animation for Autumn evenings. Created using Stellarium and GIMP.

Eclipsing Binary Star

Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky

 

10/16/2017 – Ephemeris – Andromeda, the chained princess

October 16, 2017 1 comment

Ephemeris for Monday, October 16th. The Sun will rise at 7:59. It’ll be up for 10 hours and 56 minutes, setting at 6:55. The Moon, 3 days before new, will rise at 5:29 tomorrow morning.

The stars of the constellations Andromeda the chained princess look like they’re supposed to be the hind legs of Pegasus the flying horse which is high in the southeast at 9 p.m. Andromeda is high in the east She is seen in the sky as two diverging curved strings of stars that curve to the left and up from the leftmost star of the Great Square of Pegasus. Her predicament was caused by her boastful mother Cassiopeia, and the wrath of the god Poseidon. She was rescued by the hero Perseus, a nearby constellation, riding his steed Pegasus. Andromeda’s claim to astronomical fame is the large galaxy barely visible to the unaided eye just above the upper line of stars, the Great Andromeda Galaxy 2.5 million light years away.

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

Addendum

Andromeda and friends

Andromeda and neighboring constellations that are related to her story. Created using Stellarium and GIMP.

Andromeda at 9 p.m. with the Great Andromeda Galaxy. Created using Stellarium.

Andromeda at 9 p.m. with the Great Andromeda Galaxy. Created using Stellarium.

The Great Andromeda Galaxy (M31). Image taken by Scott Anttila.

The Great Andromeda Galaxy (M31). Image taken by Scott Anttila.  It appears here more extensive than it appears visually to the naked eye or in telescopes.

11/24/2016 – Ephemeris – The little constellation that used to start the seasonal year

November 24, 2016 Comments off

Ephemeris for Thanksgiving Day, Thursday, November 24th.  The Sun will rise at 7:52.  It’ll be up for 9 hours and 14 minutes, setting at 5:06.  The Moon, 3 days past last quarter, will rise at 3:54 tomorrow morning.

From antiquity, the first constellation of the Zodiac has been Aries the ram.  That’s the constellation the Sun entered on the first day of spring, or the vernal equinox.  Well that was a couple of thousand years ago.  Currently the vernal equinox point is in western Pisces.  This is due to the wobbling of the Earth’s axis called precession.  The spinning Earth like and top or gyroscope wobbles when force is applied to it.  In this case the Sun and Moon.  One wobble takes 26,000 years to complete.  Anyway, Aries is a small constellation of four stars in a bent line, below the triangular constellation of Triangulum, which is itself below Andromeda.  It’s a bit west or right of the Pleiades or Seven Sisters star cluster.

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

Addendum

Aries the ram

Aries the ram animated finder chart for 9 p.m. November 24, 2016. Created using Stellarium and GIMP.

The vernal equinox today

The vernal equinox today, where the blue line, the celestial equator and the orange line, the ecliptic or path of the Sun cross. The Sun is where these lines cross on the first day of spring (March 20th around here). Note that the vernal equinox is now in western Pisces. Created using Stellarium.

The vernal equinox in AD 100

The vernal equinox back in AD 100, where the blue line, the celestial equator and the orange line, the ecliptic or path of the Sun cross. The Sun is where these lines cross on the first day of spring. Note that the vernal equinox was at the east edge of Pisces. Created using Stellarium.

10/31/2016 – Ephemeris – What’s a Halloween sky without the Ghoul Star

October 31, 2016 Comments off

Ephemeris for Halloween, Monday, October 31st.  The Sun will rise at 8:20.  It’ll be up for 10 hours and 12 minutes, setting at 6:32.  The Moon, 1 day past new, will set at 7:28 this evening.

Not all the ghosts and goblins out tonight will be children.  One is out every night, because it’s a star.  Its name is Algol, from the Arabic for Ghoul Star or Demon Star.  The Chinese had a name for it that meant ‘piled up corpses’.  It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening.  The star is located where artists have drawn the severed head of Medusa, whom he had slain.  Medusa was so ugly that she turned all who gazed upon her to stone.  Algol is her still glittering eye.  Astronomers finally found out what was wrong with Algol.  It does a slow 6 hour wink every 2 days 21 hours because it is two very close stars that eclipse each other in that period.  It did so this morning at 5:53 a.m.

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

Addendum

To run an app to calculate times for the minima of Algol click here:  http://www.skyandtelescope.com/observing/celestial-objects-to-watch/the-minima-of-algol/ courtesy of Sky and Telescope Magazine.

Perseus with Cassiopeia and Andromeda in the northeast at 9 p.m. October 20, 2016. Created using Stellarium and GIMP

Perseus with Cassiopeia and Andromeda in the northeast at 8:30 p.m. on Halloween.  Created using Stellarium and GIMP.

Eclipsing Binary Star

Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky

 

 

 

10/20/2016 – Ephemeris – Perseus: Is it a hero or a chicken?

October 20, 2016 Comments off

Ephemeris for Thursday, October 20th.  The Sun will rise at 8:05.  It’ll be up for 10 hours and 43 minutes, setting at 6:48.  The Moon, 2 days before last quarter, will rise at 10:54 this evening.

Positioned below the W shaped constellation of Cassiopeia half way up the sky in the northeast at 9 p.m. is the constellation of Perseus the hero of Greek myth who slew Medusa and rescued and married Andromeda represented in the constellation above and right of him.  Rather than a hero the star pattern seems to look like a chicken or perhaps Big Bird.  At least, that’s how I see it.  In the back of the chicken is its brightest star Mirfak (Mirphak).  Binoculars will show a beautiful group of stars near Mirfak just below unaided eye visibility called the Alpha Persei Association.  Tomorrow morning will see the peak of the Orionid meteor shower, though all but the brightest meteors will be overwhelmed by waning gibbous Moon.

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

Addendum

Perseus with Cassiopeia and Andromeda in the northeast at 9 p.m. October 20, 2016. Created using Stellarium and GIMP

Perseus with Cassiopeia and Andromeda in the northeast at 9 p.m. October 20, 2016. Created using Stellarium and GIMP.