APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

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APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by APOD Robot » Sat Oct 08, 2016 4:05 am

Image Moon, Mercury, and Twilight Radio

Explanation: Sharing dawn's twilight with the Moon on September 29, Mercury was about as far from the Sun as it can wander, the innermost planet close to its maximum elongation in planet Earth's skies. In this colorful scene fleeting Mercury is joined by a waning sunlit lunar crescent and earthlit lunar nightside, the New Moon in the Old Moon's arms. Below is the Italian Medicina Radio Astronomical Station near Bologna with a low row of antennae that is part of Italy's first radio telescope array dubbed the "Northern Cross", and a 32-meter-diameter parabolic dish. Of course, moonwatchers won't have to rise in early morning hours on October 8. After sunset the Moon will be high and bright in evening skies, at its first quarter phase for International Observe the Moon Night.

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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by Cobolguy » Sat Oct 08, 2016 5:08 am

You got it backwards. It is the Old Moon in the New Moon's arms.

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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by Boomer12k » Sat Oct 08, 2016 5:45 am

Nice Pic,
Heeeelloooooooo Universe.... welcome to Twilight Radio...listening for YOUR SIGNALS OF LUUUUUUUUVVVVVVVV!!!!!

I am hoping for good weather Sunday night to take out the 8" scope for more tests.
sigh...

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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by Chris Peterson » Sat Oct 08, 2016 2:45 pm

Cobolguy wrote:You got it backwards. It is the Old Moon in the New Moon's arms.
Well, it's a bit tricky to define if the earthshine lit portion of the Moon is "old" or "new", but the crescent is an old Moon, not a young one, since it's waning. So the arms, at least, are old.

Seems like one of those expressions that could reasonably by used either way.
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by ta152h0 » Sun Oct 09, 2016 12:30 am

My wife's 1st grade class is studying phases of the moon . This will be shown on Monday
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by Ann » Sun Oct 09, 2016 4:03 am

Chris Peterson wrote:
Cobolguy wrote:You got it backwards. It is the Old Moon in the New Moon's arms.
Well, it's a bit tricky to define if the earthshine lit portion of the Moon is "old" or "new", but the crescent is an old Moon, not a young one, since it's waning. So the arms, at least, are old.

Seems like one of those expressions that could reasonably by used either way.
From my latitude, the Moon is either full or lit more on one side. The crescent Moon is always lit on one side, never at top or at bottom.

I learned how to tell the waxing and the waning Moon apart by saying this: If the Moon looks like a comma, it's coming. But if it looks like a G (well, more or less like a G), it's going.

Of course, in English the expression "The Moon is coming" has some unwanted connotations. It doesn't in Swedish, unless you are definitely discussing things pertaining to that subject. (Well, you know, the ancient Greeks thought of the Moon as a goddess.)

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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by Chris Peterson » Sun Oct 09, 2016 4:11 am

ta152h0 wrote:My wife's 1st grade class is studying phases of the moon . This will be shown on Monday
Your wife is in first grade?
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by geckzilla » Sun Oct 09, 2016 4:29 am

Presumably she's in first grade ... as the teacher.
Just call me "geck" because "zilla" is like a last name.

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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by ta152h0 » Sun Oct 09, 2016 7:25 pm

I believe astronomy wizzards like Mr Peterson are funny at times. I robbed the cradle
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by neufer » Sun Oct 09, 2016 8:44 pm

ta152h0 wrote:
My wife's 1st grade class is studying phases of the moon.
Click to play embedded YouTube video.
ta152h0 wrote:
geckzilla wrote:
Chris Peterson wrote:
Your wife is in first grade?
Presumably she's in first grade
... as the teacher.
I believe astronomy wizards like Mr Peterson are funny at times. I robbed the cradle
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by ta152h0 » Sun Oct 09, 2016 10:24 pm

They just began, this year, a science block in the curriculum. She is doing quite well, getting good grades that is going to pull up her aggregate score when she graduates and begins second grade next August. The humor exhibited here by the intellectuals is heart warming personally.
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by MarkBour » Mon Oct 10, 2016 3:01 am

Chris Peterson wrote:
Cobolguy wrote:You got it backwards. It is the Old Moon in the New Moon's arms.
Well, it's a bit tricky to define if the earthshine lit portion of the Moon is "old" or "new", but the crescent is an old Moon, not a young one, since it's waning. So the arms, at least, are old.

Seems like one of those expressions that could reasonably by used either way.
I think the expression "the old Moon in the new Moon's arms" is more commonly seen, and perhaps this initially was the only version people used. But the Sun keeps catching up to the Moon (from our earthbound perspective). So, a regular occurrence in dawn or predawn skies when the moon has waned to a thin crescent would be a configuration one could call "the new Moon in the old Moon's arms". Then, there is the new Moon, possibly an eclipse, and the Sun passes the Moon (from our perspective). After that you have a near-sunset event in the early evening, as a new crescent Moon begins to wax which would be "the old Moon in the new Moon's arms".
Our professional astronomers for APOD have used this version before, and I think they're being intentional in their usage https://apod.nasa.gov/apod/ap120324.html.
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by neufer » Mon Oct 10, 2016 5:36 am

MarkBour wrote:
Chris Peterson wrote:
Cobolguy wrote:
You got it backwards. It is the Old Moon in the New Moon's arms.
Well, it's a bit tricky to define if the earthshine lit portion of the Moon is "old" or "new", but the crescent is an old Moon, not a young one, since it's waning. So the arms, at least, are old.

Seems like one of those expressions that could reasonably by used either way.
I think the expression "the old Moon in the new Moon's arms" is more commonly seen, and perhaps this initially was the only version people used. But the Sun keeps catching up to the Moon (from our earthbound perspective). So, a regular occurrence in dawn or predawn skies when the moon has waned to a thin crescent would be a configuration one could call "the new Moon in the old Moon's arms". Then, there is the new Moon, possibly an eclipse, and the Sun passes the Moon (from our perspective). After that you have a near-sunset event in the early evening, as a new crescent Moon begins to wax which would be "the old Moon in the new Moon's arms".
Our professional astronomers for APOD have used this version before, and I think they're being intentional in their usage https://apod.nasa.gov/apod/ap120324.html.
I think the expression "new Moon in the old Moon's arms" may make some vague sort of astronomical sense but the more traditional "old Moon in the new Moon's arms" is [Omar Khayyám?] poetical [and not astronomical] and refers to the Islamic idea of a new moon being a crescent moon in its waxing phase:
https://en.wikipedia.org/wiki/New_moon wrote: <<In astronomy, new moon is the first phase of the Moon, when it orbits as seen from the Earth, the moment when the Moon and the Sun have the same ecliptical longitude. The Moon is not visible at this time except when it is seen in silhouette during a solar eclipse when it is illuminated by earthshine.

The Islamic calendar has retained an observational definition of the new moon, marking the new month when the first crescent moon is actually seen, and making it impossible to be certain in advance of when a specific month will begin (in particular, the exact date on which Ramadan will begin is not known in advance).>>
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Re: APOD: Moon, Mercury, and Twilight Radio (2016 Oct 08)

Post by MarkBour » Mon Oct 10, 2016 6:26 am

neufer wrote:... the more traditional "old Moon in the new Moon's arms" is [Omar Khayyám?] poetical [and not astronomical] and refers to the Islamic idea of a new moon being a crescent moon in its waxing phase ...
Hmmm ... now the light that lights up the crescent travels from the Sun to the Moon to Earth. The light in the dimmer earthshine portion travelled from Sun to Earth (which is farther than the Moon from the Sun) and then to the Moon, and then back to Earth for us to see it. So, in either configuration, the light in the dimmer portion has travelled 2x the Earth-Moon distance farther than the light on the crescent (I think, typically 2.6 seconds).

So, perhaps it is more correct to refer to both of these as "the old sunlight in the new sunlight's arms". :ssmile:
Mark Goldfain

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