THE SOUTHWORTH PLANETARIUM

207-780-4249   www.usm.maine.edu/planet

70 Falmouth Street   Portland, Maine 04103

43.6667° N                   70.2667° W 

Altitude:  10 feet below sea level

Founded January 1970
Julian Date: 2458814.16

2019-2020:  LIX

THE DAILY ASTRONOMER

Tuesday, November 26, 2019

November Night Sky Tour

Evening

Venus and Jupiter:  line up in the western evening sky

5:00 p.m.

A despairing time for those tortured souls who prefer light to darkness.  Deepest autumn has set upon us and colliered night descends in the late afternoon instead of early evening.     Be joyful, however, for our sky bedazzles us with celestial lights.      Well over in the west, one can see the twin planetary jewels, Jupiter and Venus, drawing ever closer together.    While Venus is about six times brighter than Jupiter, both worlds outshine all the night sky stars.      Be aware that even though the moon is new tonight and therefore not visible, it will ascend as a waxing crescent in the western evening late this week.  We shall see the trinity of the dark sky's brightest lights: Moon, Jupiter and Venus gathered above the fading twilight.    Tonight, the two planets stand alone and apart.

Cassiopeia: the rising queen

7:00 p.m.

The ancient queen Cassiopeia ascends toward her apex high in the northern sky.   Like the other circumpolar constellations, this star pattern describes a circle centered on the north celestial pole, the position of which Polaris approximates.    Though the five stars comprising the main pattern seem as though they are positioned side by side, they are located at varying distances from Earth.  For instance, whereas Schedar (the second star from the right) consists of four stars about 228 light years from us, Ruckbat (the second star from the left) is an eclipsing binary star almost exactly 100 light years away.   The eclipses are difficult to observe as the brightness diminishes only slightly and successive eclipses are separated by more than two years.     A reminder that stars are akin to snowflakes: when perceived from a distance, they seem white and nondescript.  Closer scrutiny reveals them to be truly complex in structure.

The Seven Sisters

9:00 p.m.
Atlas's daughters rise into greater prominence by mid evening.    Looking very much like a smudge of light poised on Taurus the bull's shoulder, this gathering of mythical females has been striving to keep three strides ahead of the lusty Orion.    Throughout these many centuries, they have maintained a healthy distance from their persistent pursuer.   Granted, they needn't bother to flee, for the stars comprising this cluster fly through the star streams at a distance of 444 light years.  Orion's component stars lurk nowhere near the Seven Sisters.  Betelgeuse, Orion's shoulder star, is nearly 200 light years farther away.  Orion's belt stars, Mintaka, Alnilam and Alnitak, are more than 1000 light years more distant.   

When observed telescopically, the Pleiades reveals dozens more component stars,  However, only in a time exposure photograph does one see the whispers of gases surrounding these stars.  Once believed to have been the residue of nebula from which the cluster formed about 120 million years ago, this cloud, called the "Maia Nebula," is merely a rarefied nebula through which the Pleiades is currently traveling.  The star light reflects off the gases, like a firefly's light illuminating a fog bank, producing a beautiful reflection nebula.

Orion the Hunter

Midnight

The midnight hour finds Orion the Hunter passing along the meridian, the imaginary line separating the eastern and western skies.   Although we're still slightly less than a month away from astronomical winter, Orion rises through the eastern sky this evening.   To look at Orion is to see stars in both infancy and toward life's end.     Betelgeuse is a bloated red supergiant due to explode as a supernova "soon," within at least one million years. (It could have exploded already.)    Within Orion's sword one finds the Orion Nebula, a furiously active starbirth region.      The blazing light it emits originates in the trapezium, an ultra hot collection of stars that impart high energy radiation into the nebula.  The nebula absorbs the energy and then re-emits it as visible light in a process called fluorescence.      

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