THE SOUTHWORTH PLANETARIUM

70 Falmouth Street  Portland, Maine 04103

(207) 780-4249   www.usm.maine.edu/southworth-planetarium

43.67° N 70.27° W

Founded January 1970

2022-2023: XCVIII

Sunrise: 5:01 a.m.

Sunset: 8:19 p.m.

Civil twilight begins: 4:25 a.m.

Civil twilight ends: 8:44 p.m.

Sun's host constellation: Taurus the Bull

Lunar phase: Waning gibbous (97% illuminated)

Moon rise: 10:38 a.m.

Moon set: 6:59 a.m. (6/6/2023)

Julian date: 2460100.29

"Once we accept our limits, we go beyond them."

-Albert Einstein

THE DAILY ASTRONOMER

Monday, June 5, 2023

June 2023 Night Sky Calendar  Part  I:

__________________________

Happy 3rd Birthday, Miranda Beatrice!

You're nothing but trouble and you get

away with almost everything.

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The true appeal  of astronomy is its lovely predictability.    Had I had the wherewithal, not to mention the resources, I could have written this calendar in the early 1980's.     Granted, considering my age at the time, the end result would have been a bit of a mess, so it would have been difficult to tell it apart from those composed in the present.   The modern day sorcery of mathematical astronomy allows us to know the precise planet locations and moon phases decades, even centuries and millennia in advance.     The ability to forecast the sky so far in future distinguishes astronomy from meteorology, where the conditions can change profoundly in literally a blink.  (We here in New England recently went from the gorgeous mid-90s to the average-looking mid-40s overnight.   According to the meteorologists and their spinning dartboards, we'll be steeped in the Stygian gloom until sometime this weekend.    Not at all miserable, of course, but merely a reminder as to why the original European settlers didn't name this region 'New Greece.')

Even though we're posting this article on the 5th, we want to start with what has just occurred.   (To be fair, astronomy and meteorology are evenly matched when it comes to explaining what happened yesterday.)

SATURDAY, JUNE 3: VENUS AT DICHOTOMY

Venus at what?!

When at dichotomy, Venus appears as a half-moon.  Just remember that when Venus is at dichotomy, it is D-shaped.        We also recall that since Venus is closer to the Sun than Earth, it exhibits a series of phases just like the moon.*  Today, we can see half of Venus'  illuminated surface.    

[Venus' phases: Note that when Venus is full it is on the far side of the Sun and not visible to us.]   Image credit: Sky and Telescope

SATURDAY, JUNE 3: FULL MOON

The Honey Moon!   June's full moon is also known as the Strawberry Moon, Mead Moon and, cruelly, the Heat Moon.   Depending on the full moon's date, the June full moon will either be the last full moon of astronomical spring or the first full moon of astronomical summer.    This year, June's full moon occurs before the summer solstice and so serves as spring's final full moon.

SUNDAY, JUNE 4:   VENUS AT GREATEST EASTERN ELONGATION

Venus is at its best.   Not only will our sister world reveal half of her bright side, she will also stray as far from the Sun as possible during this orbit.  Tonight, Venus will appear 45 degrees from the Sun.    Incidentally, the fact that Venus is 45 degrees from the Sun in our sky while being at dichotomy is no coincidence.     

TUESDAY, JUNE 6: MOON AT PERIGEE

We should always remember that our moon does not travel along a circular orbit, but instead moves along a slightly elliptical path.  Consequently, its distance from Earth changes continually.  During every orbit, the moon reaches perigee, its point of least distance.  Approximately two weeks later, it reaches apogee, its point of greatest distance.   Today, at the precise moment of perigee, the moon will be 364,861 km from Earth.  Still a formidable travel distance.

FRIDAY, JUNE 9:  MOON NEAR SATURN

Tonight one will see the waning gibbous moon (64% illuminated) passing south of Saturn, the most distant of all the naked eye planets.    Both bodies will rise by 1:00 a.m. within the Aquarius constellation.  

SATURDAY, JUNE 10: LAST QUARTER MOON

WEDNESDAY, JUNE 14: MOON NEAR JUPITER (BRONZE EVENT!)

Jupiter has returned to the sky, albeit just before dawn.  One will see the moon passing south of this gargantuan planet within the constellation Aries the Ram.

PART II tomorrow.

*Galileo's observation of Venusian phases lent evidence in support of the Copernican notion that the planets revolve around the Sun, not Earth. 

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