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: 2458757.5
2019-2020:  XXI
             "Heavens on the half shell."
                

THE DAILY ASTRONOMER
Tuesday, October 1, 2019
October 2019 Night Sky Calendar   Part I

THURSDAY, OCTOBER 3:  MOON NEAR JUPITER
The waxing crescent moon (29% illuminated) appears to pass near the brilliant planet Jupiter tonight.   As Jupiter is currently slightly brighter than Sirius, neither the moon nor the planet will be difficult to observe.    This close passage is illusory, as the moon's distance today is about 235,000 miles.  Jupiter is presently 513.4 million miles from Earth.  The moon's greater prominence is a result of its closer proximity.

SATURDAY, OCTOBER 5:  FIRST QUARTER MOON
The first quarter moon that occurs in early autumn is low in the sky.  The first quarter moon is 90 degrees from the Sun.  So, too, is the low winter solstice point along the Sun's path, called the "ecliptic."   As the moon's motions are confined to a belt centered on the ecliptic, the moon will loiter around the winter solstice region tonight. Its low arc will convey it from the southeastern to the southwestern sky.   In the Greater Portland area, it will rise at 2:15 p.m. and set at 11:25 p.m.

SATURDAY, OCTOBER 5: MOON NEAR SATURN
The first quarter moon will help observers find Saturn tonight, as the ringed world is six times dimmer than Jupiter.     One will observe both the moon and planet within the southern constellation Sagittarius the Archer.    Lamentably, the lunar light interference will obscure the rich starfields around Sagittarius.  

Q2pXs5AVF59BUBKysHpEP5-320-80.jpg
Sagittarius will host Saturn and the moon this evening.  As slow moving Saturn completes an orbit around the Sun once every 29.5 years, it spends long periods of time in each host constellation.   Saturn will remain in Sagittarius until April 2020.  

MONDAY, OCTOBER 7:  BRILLIANT INTERNATIONAL SPACE STATION FLY OVER
We'll see the International Space Station quite a few times in October.  However, I wanted to include this "fly over," as the station will nearly pass overhead. Also, at its brightest, it will shine as brilliantly as Venus.     Refer to the starmap  below

The station rises in the west-northwest at 7:09 p.m.  When it rises, the ISS will be about as bright as Deneb, the alpha star in Cygnus the Swan.   The station will pass north of Bootes and will slice across Hercules' knee.  At 7:14 p.m. it will attain its maximum altitude of 81 degrees.  At this moment, the ISS will be as bright as Venus.  After passing through the Summer Triangle, it will fade while moving toward the southeast.   The ISS vanishes into the shadow in the southern Aquarius region (altitude 18 degrees) at 7:17 p.m.  Just before disappearing, the ISS will be as bright as Jupiter.  

PassSkyChart2.ashx.png

THURSDAY, OCTOBER 10:   APOGEE MOON
Nothing to see, really.   Consider this an academic event.     The moon will be at its greatest distance from Earth (405,899 kilometers) today.   The moon travels along an elliptical orbit, as do the planets.  Consequently, its distance from Earth varies from a near point (perigee) to a far point (apogee).  The period of time separating successive perigees (called an anomalistic month) is about 27.4 days.  The duration between successive full moons (called a synodic month) is about 29,5 days.  As these durations are different, the moon is not usually at either perigee or at apogee when full.  When the moon is full at or near perigee, we experience a "super moon."  When the moon is full at or near apogee, we experience a "micro moon."  A super moon is 14% larger and 30% brighter than a micro moon.

SUNDAY, OCTOBER 13:  FULL MOON

ce2cdbe1-fe71-4e63-96d2-ffd47eefadef-large16x9_ae5bbf35135b4c2388f145817b91c32clarge16x9_21318997_10155684930317445_6084564128971018135_o.jpg

The Hunter's moon!    The Harvest Moon, defined as the full moon closest to the autumnal equinox, can occur in either September or October.   The following full moon is termed "The Hunter's Moon."    This year, the Harvest Moon occurred in September and the Hunter's Moon fell in October.  (In 2020, the Harvest and Hunter's Moon both happen in October).  The full moon casts a luster onto the land, enabling hunters and others to navigate around the obstructions the night world generally conceals.



TO SUBSCRIBE OR UNSUBSCRIBE FROM THE "DAILY ASTRONOMER" LIST-SERVE: