Posts Tagged ‘Pinwheel Galaxy’

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.


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.


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.

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.


The change in the Big Dipper over time.

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

Alkaid and the Big Dipper

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


The Whirlpool Galaxy, M51. Credit Scott Anttila.


The Pinwheel Galaxy, M101. Credit Scott Anttila.

09/13/11 – Ephemeris – Supernova in the Pinwheel Galaxy

September 13, 2011 Comments off

Tuesday, September 13th.  The sun will rise at 7:18.  It’ll be up for 12 hours and 38 minutes, setting at 7:57.   The moon, 1 day past full, will rise at 8:05 this evening.

There is currently a supernova in a galaxy near the handle of the Big Dipper.  The bright moon is interfering with its visibility in telescopes.  It’s in a galaxy called M101 or the Pinwheel galaxy, a difficult to spot galaxy between and above the two end stars of the handle of the Big Dipper.  The galaxy is 21 million light years away, relatively close as galaxies go.  It is being intensely studied because it is of a type, 1a, that is used for distance measurements of far more distance galaxies.  This kind of Supernova is thought to be the destruction of a white dwarf star in a close binary relation with a more massive star and is drawing matter off the larger star.  When the dwarf reaches 1.38 times the sun’s mass…  Kablooey!  Astronomers are trying to see if that’s true for this star.

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