THE SOUTHWORTH PLANETARIUM

70 Falmouth Street      Portland, Maine 04103

(207) 780-4249      usm.maine.edu/planet

43.6667° N    70.2667° W 

Founded January 1970

2022-2023: XXIII

Sunrise: 6:41 a.m.

Sunset: 6:18 p.m.

Civil twilight ends: 6:47 p.m.

Sun's host constellation: Virgo the Maiden

Moon phase: Waxing gibbous (55% illuminated)

Moonrise: 3:21 p.m.

Moonset: 11:56 p.m.

Julian date: 2459856.21

"Our life is frittered away by detail...simplify, simplify."

-Henry David Thoreau

THE DAILY ASTRONOMER Monday, October 3, 2022

October 2022 Night Sky Calendar Part I

Why do we adore October?

Apart, of course, from the frost ridges along dessicated leaves, steam swirls rising out of hot apple cider mugs, and lumbering battalions of the disinterred dead marching inexorably out of the mist-enshrouded churchyards.   We adore October because even though the summer stars are exiting stage west, the brilliant winter patterns are now ascending in the mid-evening and are all in full view after midnight.       The first of the only two fully autumnal months, October marks the real transition between the consistent summer warmth and onset of winter chill.    As the nights are growing longer, albeit colder, one can venture out earlier to view the heavens.  As always, there is so much to see and admire.  This calendar, however, consists only of a comparatively few "noteworthy" events.  

SUNDAY, OCTOBER 2: FIRST QUARTER MOON

A perfect opportunity to mention what appears to be an inconsistency in sky calendars. Another almanac might indicate that the First Quarter Moon occurs on October 3rd, not 2nd. Why the discrepancy? It's simple. Some almanacs will list their events according to UT, or Universal Time, the time zone corresponding to the Prime Meridian. For instance, the first quarter moon occurs at 12:14 a.m. UT, October 3rd. This time corresponds to 8:14 p.m. EDT (Eastern Daylight Time.) This time refers to the precise moment when the moon reaches first quadrature. Even though they seem to persist over 1 - 3 nights, the first quarter moon, full moon and last quarter moon are all instantaneous events.

TUESDAY, OCTOBER 4: MOON AT PERIGEE

The moon does not travel along a perfectly circular orbit. If it did, its distance from Earth would remain constant during each revolution. Instead, the moon moves along an elliptical orbit with Earth at one focus. Consequently, the moon's distance continually changes, vacillating between a closest point, perigee, to a most distant point, apogee. Tonight, at the exact moment the moon reaches perigee, it will be 369,325 kilometers (228,981 miles) from the planet. A supermoon occurs when the moon is full around the time it reaches perigee. We have no special name for a first quarter moon that occurs around perigee...yet.

WEDNESDAY, OCTOBER 5: MOON NEAR SATURN

Saturn doesn't dazzle like Jupiter and so is more difficult to observe. One will find this distant ringed world just north of the waxing gibbous moon (80% illuminated). Both worlds will be visible just after sunset in the eastern sky and they'll both sey by 2:30 a.m.

SATURDAY, OCTOBER 8: MOON NEAR JUPITER (SILVER EVENT!!)

Venture outside during dusk to see brilliant Jupiter materialize just north of the waxing gibbous moon (93% illuminated.) Both worlds will rise by 6:00 p.m. and will be easily visible by the time civil twilight ends at 6:49 p.m.

SATURDAY, OCTOBER 8: MERCURY AT GREATEST WESTERN ELONGATION

A perfect time to see Mercury in the eastern pre-dawn sky. Mercury extends as far from the Sun as possible during this go-around and so its apparition will prove favorable. That having been said, Mercury remains always elusive and therefore difficult to observe. Mercury rises this morning at 5:14 a.m, about half an hour earlier than the onset of nautical twilight.

SUNDAY, OCTOBER 9: FULL MOON

The Hunter's Moon! The Hunter's Moon immediately follows the Harvest Moon, defined as the full moon occurring nearest the autumnal equinox. Just as the Harvest Moon supplied a persistent night light to farmers, the Hunter's Moon imparts that guiding light for the benefit of hunters. A bit nonsensical, actually, considering that the moon goddess Diana was also a protector of wild animals, but, well, there it is. October's full moon is also known as the "Dying Grass Moon," and the "Blood Moon," the latter presumably in reference to the hunted animals. In some years, October's full moon will be known as the "Harvest Moon," as it will occur closer to the autumnal equinox than the full moon that occurs in September.

Part II tomorrow.

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