Pluto Surface Observations 3: NH Post-Encounter Phase, 1 Feb 2016- TBD |
Pluto Surface Observations 3: NH Post-Encounter Phase, 1 Feb 2016- TBD |
Jul 17 2018, 09:42 AM
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#136
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Member Group: Members Posts: 241 Joined: 16-May 06 From: Geneva, Switzerland Member No.: 773 |
The image processing techniques also progressed a lot and I'm convinced that the Voyager images still hide some "secrets". A nice example is in the second paper I've mentioned earlier which compares the topography of Charon's Oz Terra with the surface of Ariel, moon of Uranus, both showing similar disrupted crustal blocks (Fig. 19 & 20).
The reprocessed Voyager images are really impressive. Marc. |
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Aug 16 2018, 05:10 PM
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#137
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
There was some discussion here of true color pictures of Pluto from NH. What I can promise here is the lowest resolution true color picture of Pluto. From the "I'll do it my damned self" files I (after a few less successful attempts) took a true color image of Pluto on August 6.
This was taken with a C 9.25", ASI-1600mm, and RGB filters, I took 40 exposures x 5 seconds in each of RGB on an object that I had verified to move between August 5 and August 6. Then after combining the color frames, I subtracted the background light pollution RGB from the entire image. And voila, Pluto in color. It is the beige dot below the white dot (star) near center. By a very lucky bit of happenstance, it is flanked on either side by very deeply (and opposite) colored stars of comparable brightness, one red and one blue, which gives some assurance that there wasn't a bias that made all dim objects appear to be one color or another. The center of my Pluto has an average RGB of about 68, 67, 59. For comparison, a "true color" image from New Horizons, blurred and set to similar brightness has an RGB of about 83, 68, 55. So we're only talking about a couple of bytes of information in this photo, and that's being generous, but at least I can tell you, this is straight from the real thing. |
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Aug 16 2018, 06:59 PM
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#138
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Member Group: Members Posts: 544 Joined: 17-November 05 From: Oklahoma Member No.: 557 |
Doesn't that also contain the color of Charon mixed in?
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Aug 16 2018, 08:15 PM
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#139
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
There was some discussion here of true color pictures of Pluto from NH. What I can promise here is the lowest resolution true color picture of Pluto. From the "I'll do it my damned self" files I (after a few less successful attempts) took a true color image of Pluto on August 6. Nice. How is the white balance set? A simple test would be to image some daylight target (eg white cloud) and see if you get equal R, G, B. |
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Aug 16 2018, 09:08 PM
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#140
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Yes, Charon is included, so this should be roughly 20% Charon and 80% Pluto.
My RGB filters are from Baader and are rotated into the optical path of a monochrome ASI-1600 camera. Because the images are taken sequentially over a period of minutes, one possible source of noise is that a wispy cloud could have passed through the line of sight and altered the gain of one or two of the channels differentially. That's not highly likely, but not impossible. I've often used this same configuration to image Venus, for example, and I could use that data (it comes out quite white) to validate the color balance of the gear. I think the lucky inclusion of quite red and blue stars flanking it close by help constrain the error, because stars only get so red and stars only get so blue, and a skew in either direction should have whitened one of those stars. I'm not sure if I can find any data on those specific stars that could be used to ground my measurements. There are brighter stars in the image (this was cropped from a 16 megapixel image and we're looking right into the plane of the Milky Way) so I could try to see if any of the stars in the image have a spectrum on record. |
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Aug 16 2018, 10:52 PM
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#141
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
I've often used this same configuration to image Venus, for example, and I could use that data (it comes out quite white) to validate the color balance of the gear. That's reassuring - I've never noticed Venus to appear other than white by eye (at least when it's high enough that reddening from Rayleigh scattering is negligible). In principle there will be white balance correction factors that the RGB channels must be multiplied by, which will depend on the bandpass of the filters and response of the sensor. |
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Oct 9 2018, 04:30 PM
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#142
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Junior Member Group: Members Posts: 80 Joined: 18-October 15 From: Russia Member No.: 7822 |
Look how far we can see beyond Pluto's terminator!
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Oct 9 2018, 06:14 PM
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#143
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
That's a great image, Roman.
If you push the brightness of the dark area up even more, the limb of Pluto appears, silhouetted against the atmosphere, which must be very faintly illuminated by light refracted from the opposite terminator. That light came a long way - I'm surprised to see it. Or could it be reflected from Charon? Phil (image subsampled from Roman's) -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 9 2018, 06:59 PM
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#144
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Junior Member Group: Members Posts: 80 Joined: 18-October 15 From: Russia Member No.: 7822 |
That's a great image, Roman. If you push the brightness of the dark area up even more, the limb of Pluto appears, silhouetted against the atmosphere, which must be very faintly illuminated by light refracted from the opposite terminator. That light came a long way - I'm surprised to see it. Or could it be reflected from Charon? Phil (image subsampled from Roman's) Thanks a lot. I worked so hard. This view would be incomplete without it. That's why I didn't crop the image. I was truly amazed when I saw it! I even can see it without increasing the brightness, so people have different brightness settings on their devices and I tried to find a balance between brightness and noise. Most curious should find this little surprise. -------------------- |
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Oct 9 2018, 09:16 PM
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#145
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Member Group: Members Posts: 706 Joined: 3-December 04 From: Boulder, Colorado, USA Member No.: 117 |
That's a great image, Roman. If you push the brightness of the dark area up even more, the limb of Pluto appears, silhouetted against the atmosphere, which must be very faintly illuminated by light refracted from the opposite terminator. That light came a long way - I'm surprised to see it. Or could it be reflected from Charon? Phil (image subsampled from Roman's) Hi Phil- We noticed that faint limb glow in 2015, and decided it was probably from Charon about to rise behind the dark limb- light from the opposite sunlit limb of Pluto wouldn't be offset like that. We'd wanted to image Charon rising or setting behind Pluto during the encounter but the timing didn't work out, so this is our consolation prize. John |
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Oct 9 2018, 09:28 PM
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#146
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
Thanks. Yes, it was the offset that made me think of Charon. What an amazing place! And just think of those other large objects out there and how amazing they must be.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 10 2018, 03:50 AM
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#147
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
So THAT'S how that shot ended up! Suggested that Charon-rise view lo those many years ago, glad to see that at least the glow was captured.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Aug 17 2019, 07:29 PM
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#148
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Junior Member Group: Members Posts: 80 Joined: 18-October 15 From: Russia Member No.: 7822 |
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Sep 20 2019, 11:49 PM
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#149
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Member Group: Members Posts: 437 Joined: 14-December 15 Member No.: 7860 |
Amazing visualization!!! Great view of Wright Mons (volcano?) !!! And if someone missed: International Astronomical Union Approves Second Set of Pluto Feature Names |
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Oct 31 2019, 09:52 PM
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#150
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Member Group: Members Posts: 866 Joined: 15-March 05 From: Santa Cruz, CA Member No.: 196 |
I didnt see this mentioned on the NH page but spaceflightinsider article shows new visual and terrain notation maps of processed far side images has been released by the team.
Now if we can just get that Pluto orbiter in the pipeline soonest, the available propulsion and gravity assist scenarios suggest it will take 18 years to reach Pluto orbit after launch, so it looks like many of us may have to hang on until 2046 for more images! |
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