Explanation: Who's watching who? The featured image of the Moon through a gap in a wall of rock may appear like a giant eye looking back at you. Although, in late October, it took only a single exposure to capture this visual double, it also took a lot of planning. The photographic goal was achieved by precise timing -- needed for a nearly full moon to appear through the eye-shaped arch, by precise locating -- needed for the angular size of the Moon to fit iconically inside the <a rhef="ap151103.html">rock arch</a>, and by good luck -- needed for a clear sky and for the entire scheme to work. The seemingly coincidental juxtaposition was actually engineered with the help of three smartphone apps. The pictured sandstone arch, carved by erosion, is millions of years old and just one of thousands of natural rock arches that have been found in Arches National Park near Moab, Utah, USA. Contrastingly, the pictured Moon can be found up in the sky from just about anywhere on Earth, about half the time.
It's beautiful (artistic, creative, imaginative, efforts to get it right) but thinking from "perfection" perspective, maybe they fell short? To me, the moon doesn't seem full seems a day before full moon. Yes ?
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 1:10 pm
by Eric
Good idea for a shot. Anyone know what might be causing the effect where the sky meets the rock?
Also, side note to Otto: "fit 'iconically' inside the rock arch"??
Eric
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 1:21 pm
by orin stepanek
Looks to me like the cave is the eye that has the Moon for a pupil!
Too bad the Moon doesn't have a ring; could be the Iris!
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 1:22 pm
by Chris Peterson
Eric wrote: ↑Wed Dec 02, 2020 1:10 pm
Good idea for a shot. Anyone know what might be causing the effect where the sky meets the rock?
I'd say the imager was a bit too aggressive with a sharpening filter. They tend to produce that type of artifact across hard contrast boundaries.
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 1:25 pm
by zelaza
Did this photo have anything to do with the steel monolith found (and removed) near Moab?
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 3:42 pm
by Phobos1
Which arch? With that many people, it's obviously one of the more famous ones. NOT "Delicate Arch".
The terrain at the park is bumpy enough that it's surprising someone could get to a stable spot far enough away to make the moon look so big inside the span. Perhaps done after talking with locals, or rangers who knew that this happened at this particular arch, sometimes, followed by a lot of measurement, calculation, and a good Hot hike?
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 3:44 pm
by neufer
Click to play embedded YouTube video.
Eric wrote: ↑Wed Dec 02, 2020 1:10 pm
...side note to Otto: "fit 'iconically' inside the rock arch"??
A pun, peut-être
https://www.etymonline.com/search?q=icon wrote:
icon (n.) also ikon, 1570s, "image, figure, picture," also "statue," from Late Latin icon, from Greek eikon "likeness, image, portrait; image in a mirror; a semblance, phantom image;" in philosophy, "an image in the mind," related to eikenai "be like, look like," which is of uncertain origin.
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 4:01 pm
by Phobos1
Eric wrote: ↑Wed Dec 02, 2020 1:10 pmAnyone know what might be causing the effect where the sky meets the rock?
With moon near full, and sun still up, the moon is waxing. You get some insane contrast effects when taking photos in the anti-solar direction at that time. Check out "anti-crepuscular rays".
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 4:32 pm
by srcapps
Who is watching WHOM?
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 4:33 pm
by orin stepanek
Eye of moon modified?
Owlice; If you don't like it; you can erase It!
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 4:44 pm
by rwlott
Who's watching whom?
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 7:12 pm
by ems57fcva
Phobos1 wrote: ↑Wed Dec 02, 2020 3:42 pm
Which arch? With that many people, it's obviously one of the more famous ones.
The text claims that the arch is millions of years old. The rock certainly is that old, but over millennia the arches come and go. If you know what to look for, you can see arches in the process of forming, just waiting for some loose rock to fall away and create the opening. And there are also cases of known arches falling down. Erosion both creates and destroys the arches.
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Wed Dec 02, 2020 8:42 pm
by neufer
ems57fcva wrote: ↑Wed Dec 02, 2020 7:16 pm
The text claims that the arch is millions of years old. The rock certainly is that old, but over millennia the arches come and go. If you know what to look for, you can see arches in the process of forming, just waiting for some loose rock to fall away and create the opening. And there are also cases of known arches falling down. Erosion both creates and destroys the arches.
The arches will noticeable chance over millennia (i.e., thousands of years). However, the whole "arches" process began roughly 65 million years ago. So, technically, the arch, itself, is millions of years old and is in its final stage of life.
<<The story of Arches begins roughly 65 million years ago. At that time, the area was a dry seabed spreading from horizon to horizon. If you stood in Devils Garden then, the striking red rock features we see today would have been buried thousands of feet below you, raw material as yet uncarved. Then the landscape slowly began to change.
First, geologic forces wrinkled and folded the buried sandstone, as if it were a giant rug and someone gathered two edges towards each other, making lumps across the middle called Anticlines. As the sandstone warped, fractures tore through it, establishing the patterns for rock sculptures of the future.
Next, the entire region began to rise, climbing from sea level to thousands of feet in elevation. What goes up must come down, and the forces of erosion carved layer after layer of rock away. Once exposed, deeply buried sandstone layers rebounded and expanded, like a sponge expands after it's squeezed (though not quite so quickly). This created even more fractures, each one a pathway for water to seep into the rock and further break it down.
Today, water shapes this environment more than any other force. Rain erodes the rock and carries sediment down washes and canyons to the Colorado River. Desert varnish appears where water cascades off cliffs. In winter, snowmelt pools in fractures and other cavities, then freezes and expands, breaking off chunks of sandstone. Small recesses develop and grow bigger with each storm. Little by little, this process turns fractured rock layers into fins, and fins into arches. Arches also emerge when potholes near cliff edges grow deeper and deeper until they wear through the cliff wall below them. In addition to grand arches, water dissolves small honeycomb formations called tafoni.
Over time, the same forces that created these arches will continue to widen them until they collapse. Standing next to a monolith like Delicate Arch, it's easy to forget that arches are impermanent. Yet the fall of Wall Arch in 2008 reminded us that this landscape continues to change. While some may fall, most of these arches will stand well beyond our lifetime: a lifetime blessed with an improbable landscape 65 million years in the making.>>
ems57fcva wrote: ↑Wed Dec 02, 2020 7:16 pm
The text claims that the arch is millions of years old. The rock certainly is that old, but over millennia the arches come and go. If you know what to look for, you can see arches in the process of forming, just waiting for some loose rock to fall away and create the opening. And there are also cases of known arches falling down. Erosion both creates and destroys the arches.
The arches will noticeable chance over millennia (i.e., thousands of years). However, the whole "arches" process began roughly 65 million years ago. So, technically, the arch, itself, is millions of years old and is in its final stage of life.
This is a matter of semantics. What is the beginning of the "life" of an arch? Is it when the sediments got laid down in such a way that arches could form? Or is it when an opening in the rocks first appeared at ground level? I would say the latter.
Re: APOD: Eye of Moon (2020 Dec 02)
Posted: Thu Dec 03, 2020 1:14 am
by neufer
ems57fcva wrote: ↑Thu Dec 03, 2020 12:16 am
This is a matter of semantics. What is the beginning of the "life" of an arch? Is it when the sediments got laid down in such a way that arches could form? Or is it when an opening in the rocks first appeared at ground level? I would say the latter.
It is indeed a matter of semantics.
IMO, the "arches" formed when salt domes formed them ~60 million years ago.
Yes, thanks, that is correct English and it has been fixed on the main NASA APOD.
Also a good link was pointed out that is now included.
Last, to clear up some confusion elsewhere, the image shown on today's APOD was claimed in an email by the photographer to be a single exposure image. The photographer noted that he did take other double exposure images -- but those appear elsewhere.
Eric wrote: ↑Wed Dec 02, 2020 1:10 pm
...side note to Otto: "fit 'iconically' inside the rock arch"??
A pun, peut-être
https://www.etymonline.com/search?q=icon wrote:
icon (n.) also ikon, 1570s, "image, figure, picture," also "statue," from Late Latin icon, from Greek eikon "likeness, image, portrait; image in a mirror; a semblance, phantom image;" in philosophy, "an image in the mind," related to eikenai "be like, look like," which is of uncertain origin.
Ah, maybe as in "eye"-con?? If that was the idea, then pox upon me for being dimmer than I thought!
Eye of Moon
