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04/12/2018 – Ephemeris – Where did the Milky Way go in the spring?

April 12, 2018 Comments off

Ephemeris for Thursday, April 12th. The Sun will rise at 7:03. It’ll be up for 13 hours and 20 minutes, setting at 8:24. The Moon, 3 days before new, will rise at 6:14 tomorrow morning.

The Bright stars of winter are sliding into the western twilight in the evening. Taking their place in the south and east are the much more sparse stars of spring. The Milky Way passes through the winter and summer skies as well as the northern autumn sky. In the spring it runs below our southern horizon. Way back 200 years ago William Herschel realized that the stars around us lie in a flattened disk, that it was deeper in the direction of the milky glow than 90 degrees from it. It wasn’t until a bit less than 100 years ago that astronomers realized that there was anything outside this disk of stars. Today we call the fuzzy objects we find out there galaxies after the Greek word for Milky Way. They were seen in the 18th and 19th centuries, but were not recognized as such.

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

Addendum

Herschel's Universe

The shape of the universe (Milky Way) as measured by William Herschel by counting stars in the eyepiece fields of his telescope pointed in various directions. The large indent on the right is caused by the Great Rift, clouds of gas and dust the block the light of the stars behind it, not the lack of stars in that direction. The Great Rift is easily seen in the summer sky running through the Milky Way.

Spring sky dome

The dome of the spring sky showing the Milky Way visible mostly on the northeastern sky. In spring, we are looking out the thin side of the Milky Way. Created using Cartes du Ciel (Sky Charts).

Some Spring Galaxies

M51 photo

The Whirlpool Galaxy, M51 in Canes Venatici. Credit Scott Anttila.

M101

The Pinwheel Galaxy, M101  near the star Mizar in the handle of the Big Dipper. Credit Scott Anttila.

Markarian Chain of galaxies in Virgo. Credit Scott Anttila.

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02/13/2018 – Ephemeris – Looking out the thin side of the Milky Way’s disk

February 13, 2018 Comments off

Ephemeris for Fat Tuesday, February 13th. The Sun will rise at 7:46. It’ll be up for 10 hours and 22 minutes, setting at 6:08. The Moon, 2 days before new, will rise at 7:07 tomorrow morning.

With Orion and the winter stars grabbing our attention in the south, let’s look to the northeast to southeast where the stars are not as many, and with the exception of the Big Dipper and some other stars, not as bright. The inner stars of the Big Dipper are part of a sparse star cluster only about 80 light years away. The reason for the sparseness is that here we are looking out the thin side of the Milky Way’s disk.  It will be our spring sky. To the west is the autumn evening skies. The thick part of the disk runs from the south-southeastern horizon, to just west of the zenith to the northwestern horizon. The reason the Milky Way isn’t as bright as the summer sections, is that we are looking away from the center to the outer spiral arms. We are in a small arm with the Great Orion Nebula.

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

Addendum

he dome of the sky

The dome of the sky at 9 p.m. February 13, 2018 showing an enhanced Milky Way. Showing also the drop off in stars off that band to the east and west. Click on image to enlarge.  Created using Stellarium.

Our place in the Milky Way.

Our place in the Milky Way. Note that we appear to be in a barred spiral galaxy.  The arms are numbered and named.  3kpc is the 3 kiloparsec arm. 1 parsec = 3.26 light years. The Sun is about 27,000 light years from the center. Credit NASA and Wikimedia Commons, via EarthSky.org

Our galactic neighborhood

Our galactic neighborhood on the Orion spur or arm. Credit R. Hurt on Wikimedia Commons, via EarthSky.org.

The summer and winter Milky Way viewing directions.

The summer and winter Milky Way viewing directions. During Spring and Autumn, we look out the sides to the universe beyond. Credit: NASA with annotations by Bob King at Universe Today.

 

09/19/2017 – Ephemeris – The Great Rift

September 19, 2017 1 comment

Ephemeris for Tuesday, September 19th. The Sun will rise at 7:26. It’ll be up for 12 hours and 18 minutes, setting at 7:45. The Moon, 1 day before new, will rise at 7:43 tomorrow morning.

High overhead the Milky Way is seen passing through the Summer Triangle of three bright stars. Here we find the Milky Way split into two sections. The split starts in the constellation of Cygnus the Swan or Northern Cross very high in the east. The western part of the Milky Way ends southwest of the Aquila the eagle. This dark dividing feature is called the Great Rift. Despite the lack of stars seen there, it doesn’t mean that there are fewer stars there than in the brighter patches of the Milky Way. The rift is a great dark cloud that obscures the light of the stars behind it. Sometimes binoculars can be used to find the edges of the clouds of the rift, as stars numbers drop off suddenly. This is especially easy to spot in Aquila the eagle.

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

Addendum

The Great Rift in the Milky Way. Created using Stellarium.

The Great Rift in the Milky Way. Created using Stellarium.

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.

08/22/2016 – Ephemeris – The glorious summer Milky Way

August 22, 2016 Comments off

Ephemeris for Monday, August 22nd.  The Sun rises at 6:54.  It’ll be up for 13 hours and 42 minutes, setting at 8:36.  The Moon, 2 days before last quarter, will rise at 11:11 this evening.

We’ll get a bit of darkness tonight, but it will be the start of about two weeks of the best sky viewing of the year.  Now is the time the summer Milky Way is displayed to its fullest to the southern horizon.  City folk come to our area and are sometimes fooled by the brightness and expanse of the Milky Way and think it’s clouding up.  Yes those are clouds indeed, but they are star clouds.  Binoculars will begin to show them to be millions of stars, each too faint to be seen by themselves to the unaided eye, but whose combined glow give the impression of a luminous cloud.  Binoculars are the ideal tool to begin to explore the Milky Way.  Objects still too fuzzy can be checked out with a telescope to reveal their true nature.

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

Addendum

Milky Way

The Milky Way from the Sleeping Bear Dunes last August by Mark Stewart.

Note that this photo shows the Milky Way as brighter and with more stars than you’d see with the naked eye.

08/05/2016 – Ephemeris – Star party at NMC’s Rogers Observatory tonight

August 5, 2016 Comments off

Ephemeris for Friday, August 5th.  The Sun rises at 6:34.  It’ll be up for 14 hours and 28 minutes, setting at 9:02.  The Moon, 3 days past new, will set at 10:31 this evening.

There will be a star party this evening at Northwestern Michigan College’s Rogers Observatory hosted by the Grand Traverse Astronomical Society and the NMC Astronomy Club starting at 9 p.m.   On tap, if it’s clear, will be Jupiter and the Moon early, then Mars and Saturn.  Mars will appear quite small.  As it gets darker the stars will appear.  Some will show companion stars, while between the stars, what we call deep sky objects will be seen.  Clusters of stars, and nebulae which can be either the birthplaces of stars or markers of dying stars.  While other galaxies can be spotted our eyes are dazzled by our galaxy, the Milky Way spanning the sky from northeast to the south, in which these other objects dwell.   The months of August and September are the months when the heart of the Milky Way is best seen.

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

Addendum

Milky Way

The Milky Way from the Sleeping Bear Dunes last August by Mark Stewart.

This year Saturn and Mars will be in the picture.  In this picture Saturn is low and to the right.

08/13/2015 – Ephemeris – The constellation Sagittarius, toward the heart of the Milky Way

August 13, 2015 Comments off

Thursday, August 13th.  The Sun rises at 6:42.  It’ll be up for 14 hours and 9 minutes, setting at 8:52.   The Moon, 1 day before new, will rise at 6:48 tomorrow morning.

The Milky Way runs from north to south through the heavens at 11 p.m. You’ll notice that the Milky Way is brighter and broader just above the horizon in the south.  In that glow in the south is a star pattern that looks like the stout little teapot of the children’s song, with a the Milky way like steam rising from the spout, which faces the west. This pattern of stars is the major part of the constellation called Sagittarius.  According to Greek mythology Sagittarius is a centaur with a bow and arrow poised to shoot Scorpius the scorpion to the right.  This centaur is called Chiron, the most learned of the breed, centaurs usually being a rowdy bunch.  The center of the pin wheel of our galaxy lies hidden beyond the stars above the spout of the teapot.

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

Addendum

Sagittarius and Scorpius

Sagittarius and Scorpius mythological view 10 p.m. August 13, 2015. Created using Stellarium.

Location of the center of the Milky Way and the Teapot of Sagittarius.

Location of the center of the Milky Way and the Teapot of Sagittarius.