APOD: Thunder Moon over Pisa (2017 Jul 18)

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APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by APOD Robot » Tue Jul 18, 2017 4:06 am

Image Thunder Moon over Pisa

Explanation: What's wrong with this picture? If you figure it out, you may then realize where the image was taken. The oddity lies actually in one of the buildings -- it leans. The Leaning Tower of Pisa has been an iconic legend since shortly after its construction began in the year 1173. Now part of a UNESCO World Heritage Site, folklore holds that Galileo used the leaning tower to dramatically demonstrate the gravitational principle that objects of different mass fall the same. Between the Leaning Tower of Pisa on the right and Pisa Cathedral and the Pisa Baptistery on the left, a full "Thunder" moon was visible last week when the image was taken. Using modern analyses, the tower has been successfully stabilized and, barring the unexpected, should hold its present tilt for the next 200 years.

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by Boomer12k » Tue Jul 18, 2017 4:09 am

And for a minute I thought it was ME leaning... boy, I am getting bad.... :lol2:

Wonderful image and planning...

Bought me a Celestron Evolution 6"... I hope it goes well. Pix soon, on the Astronomy Related Forum...

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by Ann » Tue Jul 18, 2017 6:00 am

Looking forward to it, Boomer!

Interesting APOD, and interesting colors. Everything in the picture is more or less the same bone-white color as the Moon, although there is a bit of color on the cathedral at lower left.
The Moon is probably a bit redder than this.
Source: http://www.texturepalace.com/asphalt-texture-3/
Of course, in reality, the Moon is about the same color as asphalt. At least it is typically as dark as asphalt. I believe that the Moon is generally a dull, asphalt-dark shade of red.

Of course, apparent color depends very highly on lightning conditions. An asphalt-dark Moon-sized body at the Moon's distance from the Sun will sharply reflect the light from the Sun, making the dark "asphalt" glow white.

I read somewhere that if you held a white sheet of paper right next to a chunk of black asphalt, but you managed to dramatically dim the light falling on the white paper and still more dramatically increase the light on the chunk of asphalt, then the asphalt would shine blindingly bright like a brilliant lantern next to a black sheet of paper.

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by neufer » Tue Jul 18, 2017 10:14 am

Click to play embedded YouTube video.
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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by stowaway » Tue Jul 18, 2017 6:24 pm

What is a Thunder Moon?

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by TOmaz » Tue Jul 18, 2017 7:29 pm

I have some doubts about position of the Moon on this picture. It is said in the text that the picture was taken "last week". Now on (say) the night 8/9 July 2017 (the Moon was full at 02:07 CEST on 9 July) I try to understand the time this picture was taken. I read from google earth that the main axis of Duomo is strictly east-west. So at the moment the picture was taken the moon was a few degrees north from the east direction. It was just rising. This seems strange because the sky is so dark, and we are speaking of the northern summer evening. When I read that the declination of the Moon on that day was some 20 degrees South of equator I know that Moon was rising at SE, not at NE. The photographer never took this picture or the date of the picture (early July 2017) is not correct. Clearly this requires some clarification!

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by neufer » Tue Jul 18, 2017 8:00 pm

TOmaz wrote:
I have some doubts about position of the Moon on this picture. It is said in the text that the picture was taken "last week". Now on (say) the night 8/9 July 2017 (the Moon was full at 02:07 CEST on 9 July) I try to understand the time this picture was taken. I read from google earth that the main axis of Duomo is strictly east-west. So at the moment the picture was taken the moon was a few degrees north from the east direction. It was just rising. This seems strange because the sky is so dark, and we are speaking of the northern summer evening. When I read that the declination of the Moon on that day was some 20 degrees South of equator I know that Moon was rising at SE, not at NE. The photographer never took this picture or the date of the picture (early July 2017) is not correct. Clearly this requires some clarification!
Good catch :!:
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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by fercapa » Tue Jul 18, 2017 8:34 pm

TOmaz wrote:I have some doubts about position of the Moon on this picture. It is said in the text that the picture was taken "last week". Now on (say) the night 8/9 July 2017 (the Moon was full at 02:07 CEST on 9 July) I try to understand the time this picture was taken. I read from google earth that the main axis of Duomo is strictly east-west. So at the moment the picture was taken the moon was a few degrees north from the east direction. It was just rising. This seems strange because the sky is so dark, and we are speaking of the northern summer evening. When I read that the declination of the Moon on that day was some 20 degrees South of equator I know that Moon was rising at SE, not at NE. The photographer never took this picture or the date of the picture (early July 2017) is not correct. Clearly this requires some clarification!
Another point to clarify is the size of the Moon.
With Google Earth I can estimate the horizontal field of view of the image by 16º.
If I am right the apparent size of the Moon is more than double.

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What's wrong with this picture?

Post by neufer » Tue Jul 18, 2017 10:06 pm

fercapa wrote:
With Google Earth I can estimate the horizontal field of view of the image by 16º.
If I am right the apparent size of the Moon is more than double.
That seems about right.
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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by RJN » Wed Jul 19, 2017 4:05 pm

TOmaz wrote:I have some doubts about position of the Moon on this picture.
This is my fault. I was initially a bit worried of a cut-and-paste Moon so, among other things, I emailed the astrophotographer requesting more information about the image. The problem was that I did not fully read nor comprehend his response, and just from a quick scan assumed some brightness changes and that everything else was fine. However, now going back over that email, the astrophotographer replied, in part, that the full moon was taken on 2017 July 9 and re-positioned, while the monuments were taken on 2017 July 3. The email contained a indication -- by my interpretation -- that the subsequent full moon was placed near to its "real" position on July 3. (I have not as yet checked this.) If so, it's a bit like some images where the foreground and background are taken from the same position but at different times. I have not yet looked into angular size issues. Even so, when I chose it and posted it to APOD, I really did think the entire image was taken in single shot, so I need to be more careful.

In general, APOD will consider all images so long as the creators tell us the whole truthful story about how the image was created. Since that appears to be true here, I will not take this image down. I will, however, adapt that APOD's text to better explain how that composite image was acquired. Also, in general, I much prefer images taken in fewer shots than cut-and-paste images.

- RJN

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by neufer » Thu Jul 20, 2017 10:59 am

neufer wrote:
TOmaz wrote:
I have some doubts about position of the Moon on this picture. It is said in the text that the picture was taken "last week". Now on (say) the night 8/9 July 2017 (the Moon was full at 02:07 CEST on 9 July) I try to understand the time this picture was taken. I read from google earth that the main axis of Duomo is strictly east-west. So at the moment the picture was taken the moon was a few degrees north from the east direction. It was just rising. This seems strange because the sky is so dark, and we are speaking of the northern summer evening. When I read that the declination of the Moon on that day was some 20 degrees South of equator I know that Moon was rising at SE, not at NE. The photographer never took this picture or the date of the picture (early July 2017) is not correct. Clearly this requires some clarification!
Good catch :!:
In fact: the orientation of the Moon (South to North) indicates the direction
towards the North Ecliptical Pole in the center of the Draco Constellation.

The difference is not important around Solstice
when the full moon, Polaris & Draco are all aligned...

...but it does make a difference around Equinox
with the rising full moon twisted clockwise in early Fall
& counterclockwise in early Spring.
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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by TOmaz » Thu Jul 20, 2017 9:01 pm

RJN wrote: This is my fault... the astrophotographer replied, in part, that the full moon was taken on 2017 July 9 and re-positioned, while the monuments were taken on 2017 July 3.
- RJN
Well, I very much appreciate the professional attitude from the editors, but here I see some indications that it is largely the astrophotographer's fault, he has some real problem distinguishing reality from fiction (composed by himself): he has this picture on his website under "Gallerie astronomia - Luna" entitled simply "Full Moon above Pisa", without mentioning at all that - if taken any time in July 2017 - this picture is a composite of Full Moon taken above the Southern horizon and glued to position above the Eastern horizon (and above the monuments). Even on the 3rd of July situation was not much different: Moon was just past the 1st quarter and it was rising just before 4 pm CEST (i.e. during the day) some 15 degrees from East toward South, so not over the monuments. The problem is not that the picture is a composite, but that the Moon is erroneously placed. I have some problems with credibility here: why would anybody include a faulty composite in a collection of his best astronomy pictures? Such "creativity" causes confusion: today during an introductory astronomy exam I asked two groups of students if they could explain to me in which direction a Full Moon around the Summer Solstice is rising in Europe. And both argued for the south-east, which is correct.

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by neufer » Fri Jul 21, 2017 2:39 am

  • Merry Wives of Windsor Act V, scene V
FALSTAFF: Let the sky rain potatoes;
  • let it thunder to the tune of Green Sleeves,
    hail kissing-comfits and snow eringoes;
    let there come a tempest of provocation,
    I will shelter me here.
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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by Case » Fri Jul 21, 2017 8:07 pm

TOmaz wrote:Today during an introductory astronomy exam I asked two groups of students if they could explain to me in which direction a Full Moon around the Summer Solstice is rising in Europe.
Ha, nice question. That was fun.
Trivia: it matters if Europe has summer for this, but it is SE for everywhere on Earth, except Antarctica, where the Full Moon is up all day around June.

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Re: APOD: Thunder Moon over Pisa (2017 Jul 18)

Post by neufer » Fri Jul 21, 2017 8:42 pm

Case wrote:
TOmaz wrote:
Today during an introductory astronomy exam I asked two groups of students if they could explain to me in which direction a Full Moon around the Summer Solstice is rising in Europe.
Ha, nice question. That was fun.
Trivia: it matters if Europe has summer for this, but it is SE for everywhere on Earth, except Antarctica, where the Full Moon is up all day around June.
... and the Arctic (e.g.,Svalbard, Norway, Europe), where the Full Moon never rises around June.
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