Pluto Surface Observations 3: NH Post-Encounter Phase, 1 Feb 2016- TBD |
Pluto Surface Observations 3: NH Post-Encounter Phase, 1 Feb 2016- TBD |
Jan 30 2016, 07:21 AM
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#101
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
This topic is for all New Horizons Pluto surface observations received after 1 Feb 2016.
-------------------- 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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Guest_MichaelPoole_* |
Nov 30 2017, 02:47 PM
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#102
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Guests |
I remember someone on a NASA website (might have been Mrs. Lakadawa but don't quote me on this) promising that true color, high resolution photos of Pluto will eventually be released? Have they been? I am not talking about that day 1 release image, but really high res. But I have only seen amateur colorizations so far. I had hope until the transmissions from NH have been announced to be finished but still no true color, high resolution photos! Have I missed anything?
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Nov 30 2017, 04:30 PM
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#103
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Member Group: Members Posts: 706 Joined: 3-December 04 From: Boulder, Colorado, USA Member No.: 117 |
The highest-resolution color image was publicly released as soon as it was received, here. However, this was enhanced color, showing more color detail than the human eye would see. If you're asking about "true color" as the human eye would see it, we might not have released a version of that image that's true color, though we've released low-resolution true-color images (e.g. here). Perhaps someone on this forum has made something closer to a true-color version of the highest res color image?
John |
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Aug 16 2018, 05:10 PM
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#104
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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, 08:15 PM
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#105
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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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#106
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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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#107
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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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