APOD: Penumbral Lunar Eclipse (2016 Oct 12)

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APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by APOD Robot » Wed Oct 12, 2016 4:05 am

Image Penumbral Lunar Eclipse

Explanation: Does this Moon look a little different to you? Although shown in spectacular detail, the full face of Earth's most familiar satellite appears slightly darker than usual, in particular on the upper left, because it is undergoing a penumbral lunar eclipse. The image was captured in Hong Kong, China, on September 16 when the Moon crossed through part of Earth's shadow -- but not the darkest where the Earth shades the entire Sun. A lunar eclipse can only occur during a full moon, and many know this particular full moon as the Harvest moon for its proximity to northern harvests. The next full moon will occur this coming Sunday. Some cultures refer to it as a Leaf Falling Moon, named for its proximity to northern autumn. The second full moon of the same month ("moonth") is sometimes called a Blue moon; meanwhile, this month features a rare second new moon, an event known to some as a Black moon.

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MountainJim

Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by MountainJim » Wed Oct 12, 2016 12:44 pm

My calendar indicated last month had a Black Moon (2nd New Moon) on 9/30/16. Was the last new moon on 9/30 or 10/01?

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Chris Peterson
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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Chris Peterson » Wed Oct 12, 2016 1:04 pm

MountainJim wrote:My calendar indicated last month had a Black Moon (2nd New Moon) on 9/30/16. Was the last new moon on 9/30 or 10/01?
The last new moon was on 1 October. But that's UT; in your time zone it was very likely 30 September.
Chris

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Steve Dutch

Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Steve Dutch » Wed Oct 12, 2016 1:36 pm

The only time you can "see" a truly full moon is during a central lunar eclipse, where the center of the moon passes through the center of the earth's shadow. This is about the closest you can get and still have the moon visible. In principle there should be a very slender shaded sector on the limb opposite the shadow.

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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Chris Peterson » Wed Oct 12, 2016 1:50 pm

Steve Dutch wrote:The only time you can "see" a truly full moon is during a central lunar eclipse, where the center of the moon passes through the center of the earth's shadow. This is about the closest you can get and still have the moon visible. In principle there should be a very slender shaded sector on the limb opposite the shadow.
And the only time you can "see" a truly new moon is during a total solar eclipse.

That said, I believe that both the new and the full moon are defined by the moment of least illumination and the moment of greatest illumination, not by 0% or 100% illumination.
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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by neufer » Wed Oct 12, 2016 2:42 pm


Chris Peterson wrote:
And the only time you can "see" a truly new moon is during a total solar eclipse.
Art Neuendorffer

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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Fred the Cat » Wed Oct 12, 2016 2:51 pm

In looking for why it's "Tycho" rather than "Brahe" crater I found this but it's still a bit mysterious. I guess I shouldn't be surprised. Selenography by Riciolli was as fresh as relativity was to heliocentrism. What’s next? :?
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heehaw

Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by heehaw » Wed Oct 12, 2016 2:59 pm

Aren't we lucky that the dark features on the Moon are clustered on the side toward us, to make the Moon so interesting to look at! But before Galileo and the telescope, there is only one (1) drawing of the Moon, and that a mere scribble. How come? The Man in the Moon is clearly and easily visible to the naked eye! Well, I have a theory! Before Galileo there were no eyeglasses. All the old Professors had lost the vision of their youth, and their memories, if any, of seeing the Man in the Moon. And when asked about it by young people, they chastised those poor young people for not knowing that all celestial was perfect; all below is tainted; the Moon was necessarily without ragged flaws.

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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by neufer » Wed Oct 12, 2016 3:15 pm

heehaw wrote:
before Galileo and the telescope, there is only one (1) drawing of the Moon, and that a mere scribble. How come? The Man in the Moon is clearly and easily visible to the naked eye! Well, I have a theory! Before Galileo there were no eyeglasses. All the old Professors had lost the vision of their youth, and their memories, if any, of seeing the Man in the Moon. And when asked about it by young people, they chastised those poor young people for not knowing that all celestial was perfect; all below is tainted; the Moon was necessarily without ragged flaws.
https://en.wikipedia.org/wiki/Man_in_the_Moon wrote:
<<There are various explanations for how the Man in the Moon came to be.

A longstanding European tradition holds that the man was banished to the moon for some crime. Christian lore commonly held that he is the man caught gathering sticks on the Sabbath and sentenced by God to death by stoning in the book of Numbers XV.32-36. Some Germanic cultures thought he was a man caught stealing from a neighbor's hedgerow to repair his own. There is a Roman legend that he is a sheep-thief.

One medieval Christian tradition claims him as Cain, the Wanderer, forever doomed to circle the Earth. Dante's Inferno alludes to this:
  • For now doth Cain with fork of thorns confine
    On either hemisphere, touching the wave
    Beneath the towers of Seville. Yesternight
    The moon was round.
This is mentioned again in his Paradise:
  • But tell, I pray thee, whence the gloomy spots
    Upon this body, which below on earth
    Give rise to talk of Cain in fabling quaint?
There is also a Talmudic tradition that the image of Jacob is engraved on the moon,[4] although no such mention appears in the Torah.

John Lyly says in the prologue to his Endymion (1591), "There liveth none under the sunne, that knows what to make of the man in the moone."

In Norse mythology, Máni is the male personification of the moon who crosses the sky in a horse-drawn carriage. He is continually pursued by the Great Wolf Hati who catches him at Ragnarok. The name Máni simply means "Moon".

In Chinese mythology, the goddess Chang'e is stranded upon the moon after foolishly consuming a double dose of an immortality potion. She is accompanied by a small group of moon rabbits.

In Haida mythology, the figure represents a boy gathering sticks. The boy's father had told him the moon's light would brighten the night, allowing the chore to be completed. Not wanting to gather sticks, the boy complained and ridiculed the moon. As punishment for his disrespect, the boy was taken from earth and trapped on the moon.>>
https://en.wikipedia.org/wiki/Glasses wrote: <<The first eyeglasses were made in Italy in about 1286, but it is not clear who the inventor was. In a sermon delivered on February 23, 1306, the Dominican friar Giordano da Pisa (ca. 1255–1311) wrote "It is not yet twenty years since there was found the art of making eyeglasses, which make for good vision... And it is so short a time that this new art, never before extant, was discovered. ... I saw the one who first discovered and practiced it, and I talked to him." Giordano's colleague Friar Alessandro della Spina of Pisa (d. 1313) was soon making eyeglasses. The Ancient Chronicle of the Dominican Monastery of St. Catherine in Pisa records: "Eyeglasses, having first been made by someone else, who was unwilling to share them, he [Spina] made them and shared them with everyone with a cheerful and willing heart." By 1301, there were guild regulations in Venice governing the sale of eyeglasses.

The earliest pictorial evidence for the use of eyeglasses is Tommaso da Modena's 1352 portrait of the cardinal Hugh de Provence reading in a scriptorium. Another early example would be a depiction of eyeglasses found north of the Alps in an altarpiece of the church of Bad Wildungen, Germany, in 1403.

These early glasses had convex lenses that could correct both hyperopia (farsightedness), and the presbyopia that commonly develops as a symptom of aging. It was not until 1604 that Johannes Kepler published the first correct explanation as to why convex and concave lenses could correct presbyopia and myopia.

Early frames for glasses consisted of two magnifying glasses riveted together by the handles so that they could grip the nose. These are referred to as "rivet spectacles". The earliest surviving examples were found under the floorboards at Kloster Wienhausen, a convent near Celle in Germany; they have been dated to circa 1400.>>
Art Neuendorffer

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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Rusty Brown in Cda » Wed Oct 12, 2016 3:32 pm

I had never heard of a "black moon" until now, and when I looked it up on one sincere but misguided website it said that it was when there was a second new moon in a month and it passed in front of the sun and obscured it.
"Total failure to grasp the basic concept".

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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Boomer12k » Wed Oct 12, 2016 10:58 pm

Thanks for the explanation...

I took out the new 8" Meade SC Light Switch scope... it has a built on camera for alignment with stars for the setup... well, it can also take pictures... it is low res 640x480, I think, but color... here is my Waxing Gibbous Moon from last night, probably the last good night for a week and a half... there is no Magnification on this camera, no zoom. It takes an automatic picture of a star's position, then readjusts the scope to center the star. Once centered it will center the next and you are ready to observe.... But you can see the Seas... as in today's APOD... it is so cool... I think with a 10-20 minute exposure I might get a good M31 even... I got a hazy patch at 4 minutes. So Cool... Mars was an Orange dot...just as you see it.
But works indoors, and terrestrially, as well.

May the Clear Skies be with you...always....to borrow a phrase.
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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by Joe Stieber » Thu Oct 13, 2016 12:54 am

Chris Peterson wrote:
Steve Dutch wrote:The only time you can "see" a truly full moon is during a central lunar eclipse, where the center of the moon passes through the center of the earth's shadow. This is about the closest you can get and still have the moon visible. In principle there should be a very slender shaded sector on the limb opposite the shadow.
And the only time you can "see" a truly new moon is during a total solar eclipse.

That said, I believe that both the new and the full moon are defined by the moment of least illumination and the moment of greatest illumination, not by 0% or 100% illumination.
Technically, Full Moon occurs when the ecliptic longitudes of the Sun and Moon differ by 180 degrees. Conversely, new moon occurs when the ecliptic longitudes of the Sun and Moon are the same.

Position is the primary consideration, illumination is secondary. That's why the First and Last Quarter Moons look about half illuminated. The quarters are fractions of it's orbit, not the illumination, unless you want to suppose that at the quarters, we're seeing half of the Moon illuminated half way (but that wouldn't work for the Full Moon).

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Re: APOD: Penumbral Lunar Eclipse (2016 Oct 12)

Post by MarkBour » Thu Oct 13, 2016 1:25 am

heehaw wrote:Aren't we lucky that the dark features on the Moon are clustered on the side toward us, to make the Moon so interesting to look at! ...
And today's APOD is a spectacularly-clear image of it, I must say.

I guess we are lucky that it happened that way. Of course there are a few good theories as to why it happened, and then you'd perhaps say it was physics, not luck. I did like the thinking presented here: http://news.psu.edu/story/317841/2014/0 ... ery-solved. But my feeling is that the cause of it is still open to question.
Mark Goldfain