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Posts Tagged ‘Polaris’

08/22/2014 – Ephemeris – Cassiopeia Rising

August 22, 2014 Comments off

Ephemeris for Friday, August 22nd.  The sun rises at 6:53.  It’ll be up for 13 hours and 43 minutes, setting at 8:36.   The moon, 3 days before new, will rise at 5:08 tomorrow morning.

Now in the northeastern sky at 10 p.m. or later is the constellation of Cassiopeia the queen, which looks like, in its current orientation like the letter W.  The Milky Way runs through it, if you trace the Milky Way from the zenith back to the northeast.  The milky band isn’t as bright here as it is in the teapot shaped Sagittarius to the south.  That’s because in looking to the south we are looking toward the star clouds of the dense spiral arm toward the center of the galaxy.  In Cassiopeia, and in the winter sky, we are looking out to the less populated galactic arms farther out from the center of the Milky Way.   Cassiopeia can be found using the Big Dipper.  A line from the star Mizar at the bend of the handle of the dipper through Polaris points to Cassiopeia.  Cassiopeia doesn’t set for us in northern Michigan.

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

Addendum

Finding Cassiopeia

Finding Cassiopeia using the Big Dipper or Ursa Major at 10 p.m. August 22, 2014 using the angle measurement tool as a pointer. Created using Stellarium.

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06/02/2014 – Ephemeris – The Big Dipper points to other stars and constellations

June 2, 2014 Comments off

Ephemeris for Monday, June 2nd.  Today the sun will be up for 15 hours and 21 minutes, setting at 9:21.   The moon, 3 days before first quarter, will set at 12:41 tomorrow morning.  Tomorrow the sun will rise at 5:59.

The Big Dipper points to other stars and constellations.  Right now the Big Dipper is nearly overhead.  The front bowl stars point to Polaris, the North Star which never seems to move in the sky.  The handle can be used to find two stars.  First follow the arc of the handle away from the bowl to find the fourth brightest night time star Arcturus in the base of the kite shaped constellation of Boötes.  Straighten the arc to a spike and continue to the south and you will come to the bright blue-white star Spica in Virgo the virgin.  Don’t confuse it with reddish Mars to the right of it now.  You can remember these stars with the phrase “Follow the arc of the handle to Arcturus and then spike to Spica”

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

Addendum

Big Dipper

The Big Dipper can be used to point to other stars and constellations in the spring sky. Credit: My LookingUp program.

09/30/2013 – Ephemeris – The constellation of Cassiopeia the queen

September 30, 2013 Comments off

Ephemeris for Monday, September 30th.  The sun will rise at 7:39.  It’ll be up for 11 hours and 44 minutes, setting at 7:24.   The moon, half way from last quarter to new, will rise at 4:07 tomorrow morning.

The stars of the autumn skies slowly are replacing the summer stars from the east.  Look in the northeastern sky by 9 p.m. and you can find the W shaped constellation of Cassiopeia the queen.  Cassiopeia is so far north that it never sets for us in Michigan.  It is opposite the pole star Polaris from the Big Dipper.  There’s a dim star that appears above the middle star of the W which turns the W into a very crooked backed chair.    Cassiopeia, in Greek mythology, represents a queen of ancient Ethiopia, the W represents the profile of her throne.  She enters in to the great autumn story whose other characters are also seen in the stars as the constellations Andromeda, Pegasus, Perseus, Cetus and her husband Cepheus.

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

Addendum

Cassiopeis, in the northeast is opposite Polaris from the Big Dipper.  For 9 p.m. on September 30th.  Created using Stellarium.  Artistic credit:  Johan Meuris.

Cassiopeis, in the northeast is opposite Polaris from the Big Dipper. For 9 p.m. on September 30th. Created using Stellarium. Artistic credit: Johan Meuris.  Click to enlarge.

11/22/2012 – Ephemeris – Celestial navigation in the days of the Pilgrims

November 22, 2012 Comments off

Ephemeris for Thanksgiving Day, Thursday, November 22nd.  The sun will rise at 7:48.  It’ll be up for 9 hours and 19 minutes, setting at 5:08.   The moon, 2 days past first quarter, will set at 2:58 tomorrow morning.

Back in the days of the Pilgrims navigation was much less certain than it is today.  At the mercy of the winds and weather, sailing took a lot of courage.  Celestial navigation took the form of measuring the altitude of the pole star Polaris at night and the sun at noon.  That and tossing a log overboard attached to a rope with knots at regular interval to gauge their speed and progress.  That’s where we get the term knots as a measure of speed for nautical and aviation use.  Today we have GPS to tell us where we are.  However that is based on the position of not stars, but quasars, bright nuclei of distant galaxies, whose motions are currently too small to measure.  Have a happy Thanksgiving.

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

Addendum

 

nasa-map_GPS Quasars

All sky map of quasar locations used as the celestial markers for the GPS system. Chart by David Bobolz, US Naval Observatory.

The chart above is from an article in the Telegraph.