APOD: Pluto in True Color (2019 Sep 10)

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APOD: Pluto in True Color (2019 Sep 10)

Post by APOD Robot » Tue Sep 10, 2019 4:05 am

Image Pluto in True Color

Explanation: What color is Pluto, really? It took some effort to figure out. Even given all of the images sent back to Earth when the robotic New Horizons spacecraft sped past Pluto in 2015, processing these multi-spectral frames to approximate what the human eye would see was challenging. The result featured here, released three years after the raw data was acquired by New Horizons, is the highest resolution true color image of Pluto ever taken. Visible in the image is the light-colored, heart-shaped, Tombaugh Regio, with the unexpectedly smooth Sputnik Planitia, made of frozen nitrogen, filling its western lobe. New Horizons found the dwarf-planet to have a surprisingly complex surface composed of many regions having perceptibly different hues. In total, though, Pluto is mostly brown, with much of its muted color originating from small amounts of surface methane energized by ultraviolet light from the Sun.

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by shaileshs » Tue Sep 10, 2019 4:14 am

I wonder why it's sooooooooo difficult (takes 3 years and several processing efforts) to figure out how it'd look to an unaided human eye.. If the spacecraft has regular camera (similar to what an ordinary cellphone has now-a-days) then an image taken in natural light (i mean, visible light, not infrared/x-ray etc) - even with a decent flash and zoom - will show us what a normal eye would see.. No ? Am I misunderstanding something ? Thanks in advance for all answers/comments.

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Chris Peterson » Tue Sep 10, 2019 4:54 am

shaileshs wrote:
Tue Sep 10, 2019 4:14 am
I wonder why it's sooooooooo difficult (takes 3 years and several processing efforts) to figure out how it'd look to an unaided human eye.. If the spacecraft has regular camera (similar to what an ordinary cellphone has now-a-days) then an image taken in natural light (i mean, visible light, not infrared/x-ray etc) - even with a decent flash and zoom - will show us what a normal eye would see.. No ? Am I misunderstanding something ? Thanks in advance for all answers/comments.
It did not take three years to produce "true color" images of Pluto. Such images were released quite early. This is merely a more refined image based on more complex processing. The spacecraft doesn't have a camera optimized for matching human vision. The colors as seen by our eyes need to be constructed from just two fairly broad bands centered on blue and red, with green information calculated in some way, possibly involving IR channels. It's not simple, especially given that some of the apparent color is not created by reflected light, but by fluorescence (the visible part possibly being estimated by looking at invisible IR emissions).
Chris

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Guest » Tue Sep 10, 2019 9:49 am

For some reason looking at Pluto makes me crave ice cream!

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Guest » Tue Sep 10, 2019 9:55 am

shaileshs wrote:
Tue Sep 10, 2019 4:14 am
I wonder why it's sooooooooo difficult (takes 3 years and several processing efforts) to figure out how it'd look to an unaided human eye.. If the spacecraft has regular camera (similar to what an ordinary cellphone has now-a-days) then an image taken in natural light (i mean, visible light, not infrared/x-ray etc) - even with a decent flash and zoom - will show us what a normal eye would see.. No ? Am I misunderstanding something ? Thanks in advance for all answers/comments.
The link in the description goes to a very nice wiki page on NH’s optics and the way color images are made...

https://en.wikipedia.org/wiki/Ralph_(New_Horizons)

It gets a little technical but it’s a good read!

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by neufer » Tue Sep 10, 2019 12:21 pm

https://en.wikipedia.org/wiki/The_dress wrote:

<<The dress is a photograph that became a viral internet sensation on 26 February 2015, when viewers disagreed over whether the dress pictured was coloured blue and black, or white and gold. The phenomenon revealed differences in human colour perception, which have been the subject of ongoing scientific investigations into neuroscience and vision science, with a number of papers published in peer-reviewed science journals.

The photo originated from a washed-out colour photograph of a dress posted on the social networking service Tumblr. Although the actual color was eventually confirmed as blue and black, the image prompted many discussions, with users debating their opinions on the colour and how they perceived the dress in the photograph as a certain colour.

There is currently no consensus on why the dress elicits such discordant color perceptions among viewers. No synthetic stimuli have been constructed that are able to replicate the effect as clearly as the original image.

Neuroscientists Bevil Conway and Jay Neitz believe that the differences in opinions are a result of how the human brain perceives colour, and chromatic adaptation. Conway believes that it has a connection to how the brain processes the various hues of a daylight sky: "Your visual system is looking at this thing, and you're trying to discount the chromatic bias of the daylight axis... people either discount the blue side, in which case they end up seeing white and gold, or discount the gold side, in which case they end up with blue and black." Similar theories have been expounded by the University of Liverpool's Paul Knox, who stated that what the brain interprets as colour may be affected by the device the photograph is viewed on, or the viewer's own expectations.

Neuroscientist and psychologist Pascal Wallisch attributes differential perceptions to differences in illumination and fabric priors, but also notes that the stimulus is highly unusual insofar as the perception of most people does not switch. If it does, it does so only on very long time scales, which is highly unusual for bistable stimuli, so perceptual learning might be at play.>>
Art Neuendorffer

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by orin stepanek » Tue Sep 10, 2019 1:02 pm

Ahh Pluto: my little buddy! Kind of looks like a road from this crater! :wink:
PlutoTrueColor_NewHorizons_960.jpg
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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by TheZuke! » Tue Sep 10, 2019 1:52 pm

Neufer's post on color perception reminded me of my experience over 30 years ago.
I was a TV repairman at a TV & Appliance store.
The two main brands of TV's we sold were RCA and Sylvania.
To me the RCA TV's gave a truer reproduction of flesh tones and the Sylvanias, to me, were somewhat orange in tone.
With each brand of TV side by side, one of our salesmen was convinced the Sylvania gave a truer flesh tone.

As an aside, some birds have 4 types of cone cells in their eyes; red, green, and 2 which respond to different wavelengths of blue.
(as opposed to red, green, and 1 blue in (most) human eyes).

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by TheZuke! » Tue Sep 10, 2019 2:02 pm

shaileshs wrote:
Tue Sep 10, 2019 4:14 am
I wonder why it's sooooooooo difficult (takes 3 years and several processing efforts) to figure out how it'd look to an unaided human eye.. [...]
Mission priorities?
While giving non-scientific observers "true color" could promote future funding for space exploration, putting the equivalent of a cell phone camera on board for that purpose would add to space craft weight and downloading such images would further tie up the already slow transmission rate in which data is transmitted.
Also, there is very little sunlight reaching Pluto, any reflected sunlight would be very dim, and therefore be interpreted by our eyes as a black and white image anyway.
(just my educated guesses, I am not in any way on any team deciding mission requirements.)

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Chris Peterson » Tue Sep 10, 2019 2:12 pm

TheZuke! wrote:
Tue Sep 10, 2019 2:02 pm
shaileshs wrote:
Tue Sep 10, 2019 4:14 am
I wonder why it's sooooooooo difficult (takes 3 years and several processing efforts) to figure out how it'd look to an unaided human eye.. [...]
Mission priorities?
While giving non-scientific observers "true color" could promote future funding for space exploration, putting the equivalent of a cell phone camera on board for that purpose would add to space craft weight and downloading such images would further tie up the already slow transmission rate in which data is transmitted.
Also, there is very little sunlight reaching Pluto, any reflected sunlight would be very dim, and therefore be interpreted by our eyes as a black and white image anyway.
(just my educated guesses, I am not in any way on any team deciding mission requirements.)
The light level at Pluto is about the same as a typical electric light illuminated living room. Plenty of light to stimulate human color vision.
Chris

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by FLPhotoCatcher » Tue Sep 10, 2019 2:49 pm

Speaking of perception... Why does everyone say that the lighter region looks like a heart? I guess early-on, when the resolution was poor, it looked Sort Of like a heart. But when higher resolution photos were available, it clearly looked like a footprint. It even looks like 'mud' splashed away when the footprint was made.

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Pluton » Tue Sep 10, 2019 2:50 pm

So grateful for this science...

What thrilled me most during actual initial approach were the first images with some discernible features, which happened to be of the opposite face.

Image

Those formations seemed, to me, to be much more fascinating than the Tombaugh Regio, which I would say is a relatively more common type of geography.

And so, I'm always waiting for enhanced images, and scientific findings, of this opposite side to be released. I'm quite surprised at the lack of attention it receives.

Does anyone know of any leads on this?

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Ann » Tue Sep 10, 2019 2:51 pm

Pluto in true color.
NASA, JHU APL, SwRI, Alex Parker




















I read somewhere that Pluto is one of the reddest large objects in the Solar System, but it is less red than Mars. Interestingly, I think that one important "color difference" between Mars and Pluto is that Pluto is much more reflective than Mars, because Pluto is an icy object and Mars is rocky. Also much of the surface of Pluto is young and therefore extra reflective.

Albedo of the planets (and the Moon and Pluto)

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by neufer » Tue Sep 10, 2019 4:15 pm

Pluton wrote:
Tue Sep 10, 2019 2:50 pm
Image
What thrilled me most during actual initial approach were the first images with some discernible features, which happened to be of the opposite face.

Those formations seemed, to me, to be much more fascinating than the Tombaugh Regio, which I would say is a relatively more common type of geography.

And so, I'm always waiting for enhanced images, and scientific findings, of this opposite side to be released. I'm quite surprised at the lack of attention it receives.

Does anyone know of any leads on this?
https://en.wikipedia.org/wiki/Cthulhu_Macula wrote:
<<The "Brass Knuckles" region of Pluto. Meng-p'o is at the zero meridian; to the east is the 'tail' of Cthulhu.

A series of semi-regularly spaced dark spots with irregular boundaries are nicknamed the Brass Knuckles. They average about 480 km in diameter and are located along the equator between the Heart and the tail of the Whale. The brass knuckles are separated from one another by tall uplands. There are also many canyons running through them and through the surrounding mountains that are hundreds of miles long and several miles deep. The Knuckles are:

Vucub-Came Macula and Hun-Came Macula, after the two leading death gods in the Popol Vuh text of the K'iche' Maya

Meng-p'o Macula, after a goddess from Chinese Buddhism who caused the dead to forget their past lives

Balrog Macula, after a fictional race of demons in J. R. R. Tolkien's fantasy mythos

Krun Macula, after a lord of the underworld in the Mandaean religion of southern Iraq

Ala Macula, after an underworld and harvest deity of the Igbo people of eastern Nigeria

A bright, ring-shaped feature about 350 km across located near the tail of the "Whale" in low-resolution images is nicknamed the "Donut". It does not appear as a ring in higher-resolution images. Cthulhu Macula is a prominent surface feature of the dwarf planet Pluto, that is reminiscent of a whale in shape. It is an elongated dark region along Pluto's equator, 2,990 km long and one of the darkest features on Pluto. It is west of the Sputnik Planitia region of Tombaugh Regio, also known as Pluto's "heart", and to the east of Meng-P'o, the easternmost of Pluto's "Brass Knuckles".

The dark color of the region is speculated to be the result of a "tar" made of complex hydrocarbons called tholins covering the surface, which form from methane and nitrogen in the atmosphere interacting with ultraviolet light and cosmic rays. Tholins have been observed on other planetary bodies, such as Iapetus, Umbriel, and in the atmosphere of Titan, although the irregular and disconnected nature of the dark spots on Pluto has not yet been explained. The presence of craters within Cthulhu indicates that it is perhaps billions of years old, in contrast to the adjacent bright, craterless Sputnik Planitia, which may be as little as 100 million years old; however, some areas of Cthulhu Macula are smoother and much more modestly cratered, and may be intermediate in age. The western 'head' region consists mostly of heavily cratered 'alpine' terrain. The middle part of Cthulhu Macula is meanwhile a smooth plain, probably formed through large cryovolcanic eruptions, like Vulcan Planum on Charon. This part appears to be younger than the alpine terrain to the east, but there are nevertheless several large craters located in this region. The western 'tail' region of Cthulhu Macula was imaged in much lower resolution than the eastern part, but it can be inferred that this is a hilly landscape bordered by mountains to the west. Higher-resolution images of the border between the two regions indicate that lighter material from Sputnik Planitia, composed of nitrogen, carbon monoxide, and methane ices, may be invading and overlaying the easternmost part of the dark Cthulhu Macula.

"Cthulhu" was named after the fictional deity from the works of H. P. Lovecraft and others. The character Cthulhu initially appeared in Lovecraft's 1928 short story "The Call of Cthulhu", as a malevolent entity hibernating within an underwater city in the South Pacific. In the book, it is the subject of worship by a number of human cults asserting that while it is currently trapped, Cthulhu will eventually return. In many of Lovecraft's stories, particularly The Whisperer in Darkness, the transneptunian planet Yuggoth is implied to be the same as Pluto, which was discovered around the time Lovecraft was writing the stories.>>
Art Neuendorffer

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by Pluton » Tue Sep 10, 2019 4:43 pm

neufer wrote:
Tue Sep 10, 2019 4:15 pm
Thank you. Yes, of course, I should have stated I've checked Wikipedia and so on. Also that it is the region North of Vucub-Came/Cthulhu Macula/Meng-p'o, that I am particularly referencing and so curious about. The obviously huge, apparently hexagonal-ish features. To me, appearing tantalizingly unnatural.

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Re: APOD: Pluto in True Color (2019 Sep 10)

Post by MarkBour » Wed Sep 11, 2019 1:29 am

I love the hi-res achieved in today's APOD (the version you get when you click on it).

Without it, I never would have seen Cthulhu's vehicle's tire tracks leading into the crater at the far left (at almost 9:00, considered as a clock face.)
Mark Goldfain