THE SOUTHWORTH PLANETARIUM
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70 Falmouth Street   Portland, Maine 04103
43.6667° N                   70.2667° W
Altitude:  10 feet below sea level
Founded January 1970
Julian date: 2458736.5
2019-2020:  VI
              "Life isn't about finding yourself. It's about creating
yourself."
                                          -George Bernard Shaw

THE DAILY ASTRONOMER
Tuesday, September 10, 2019
The Setting Pole

Today we'll focus on a sight we actually can't see.
Well, yes, that does seem rather pointless, doesn't it?  However, the
purpose of this exercise isn't to admire one of the myriad celestial
wonders floating in the void around Earth.   The aim is to get our bearings
in the Milky Way Galaxy, that immense maelstrom of nearly 300 billion stars
through which our solar system is rapidly moving at 143 miles per second.
The image below depicts the galaxy as envisioned by artist R. Hurt at
Cal-Tech.

[image:
1024px-Artist's_impression_of_the_Milky_Way_(updated_-_annotated).jpg]
*Home:*  A Cal Tech artist created this image of the Milky Way Galaxy.  Our
Solar system
is located along the "Orion Spur" within the Orion-Cygnus Arm.    The Milky
Way is a
barred spiral galaxy whose main structure consists of curling arms
protruding out of a
central "bar."    Image:  NASA

Our solar system is about 26,080 light years from the nucleus, a region
harboring a super massive black hole within the area of Sagittarius.   When
one looks at the constellation Sagittarius, one is observing the central
part of the galaxy.  Or, more correctly, the highly obscured region
surrounding the nucleus.    One can find the star-rich region of
Sagittarius this evening in the southwestern sky.

Today, however, we want to focus on the North Galactic Pole:  the line of
sight that directs our gaze out of the galactic plane and into the wild
black yonder of extra galactic space.       The next image depicts another
artistic impression of the North Galactic Pole, or at least the direction
toward it.   As we humans haven't even ventured half a million miles from
Earth, let alone to another planet or out of the solar system, we can't
provide any direct views outside the Milky Way Galaxy.


[image: galacticcoords.2.jpg]

Looking toward the North Galactic Pole is as easy as looking at the
constellation Coma Berenices, the "hair" star pattern to the west of
Arcturus, the bright star one will find in the western evening sky tonight.
Coma Berenices will soon be setting into the dusk and with it shall go the
North Galactic Pole.    Unlike the North Celestial Pole, which is marked
approximately by Polaris, the North Galactic Pole has no prominent marker.
Just first find Arcturus and then look to the northwest to see a dark area
above it.  That nothingness will be the open area perpendicular to the
galactic plane: into the boundless deeps of extragalactic space.


[image: sherrod-galacticpole.jpg]


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