I Dawn dead in Ceres orbit, ran out of fuel Oct 2018

[marcus]

Reprehensible babbling!

It was a spoonerism for "straight poop"
more commendatory than derogatory.

 

[OmCheeto]

It was a spoonerism for "straight poop"
more commendatory than derogatory.

Phew!
I was afraid you and Dr. Rayman were corresponding behind my back.

Dr. Ramen; "Marcus, will you please tell Om to slow down on the prate stoop...".​

I do look back at some of my comments, and think; "That was reprehensible babble. It's obvious I didn't even bother engaging my brain".

But, that's nothing new.

ps. On a hopefully not true side note, I had an argument with someone at JPL a couple of weeks ago. I'm assuming it wasn't Dr. Rayman:

May 21, 2015 9:24 AM

Good morning Marc,

So that wasn’t you I was arguing with on Facebook?
Someone asked;

Joseph Johnson

Why are there never any stars in these pictures?
15 May at 10:32​

To which I responded, and appear to have started an argument:

Om

Here's one of Ceres and some stars taken on Dec 1, 2014.
Enhanced Early View of Ceres from Dawn
15 May at 21:30​

NASA Dawn Mission

When you see stars on an image from Dawn... they have been added to the image! Charming, but not the real deal, for all the reasons noted, not enough exposure time...
16 May at 17:39​

Om

Well... The link to the Dec 1 image does imply that there were some photographic shenanigans, but I do believe the stars were captured by Dawn's camera; "Ceres is the bright spot in the center of the image. Because the dwarf planet is much brighter than the stars in the background, the camera team selected a long exposure time to make the stars visible. The long exposure made Ceres appear overexposed, and exaggerated its size; this was corrected by superimposing a shorter exposure of the dwarf planet in the center of the image." Someone get the Max Planck Institute on the line!
16 May at 18:04​

I guess, technically, we are both correct.​

No word since.

pps. Followers
Facebook: 19k
Twitter: 84k

As is usually the case, 95% of the comments on Facebook, are prate stoop(not a spoonerism, by my favorite new phrase).
I wouldn't even bother checking it out, as most of the posts mirror the Twitter site.

 

[marcus]

Om, Canberra 45 is standing by to talk with Dawn! It is 2AM in the morning there (9AM pacific 2 June).

Maybe a prate stoop means a kind of humorous indirection where one arranges to stumble on the straight story seemingly by accident. A kind of serendipitous pratefall which lands on the essential fact.

Hey! Simview is using a beautiful new globe map of Ceres instead of the old Lumpy guess-ball

The 19:30 UTC simview even has the famous double bright spot showing. The new Ceres ball in simview is made of real photos taken by Dawn, with some latitude and longitude lines projected on it.

 

[marcus]

The new Ceres globe has number-coded REGIONS NAMED AFTER OTHER CULTURES' GRAIN/FERTILITY GODDESSES projected on the map of real craters and features and bright spots and scratches. If they actually wrote out the names, this will be very tedious to duplicate in Om's customary fashion either with a log or using a sportive ball of some nondescript type like volley or basket.
Most of these grain goddesses' names are strange and hard to spell.

 

[OmCheeto]

The new Ceres globe has REGIONS NAMED AFTER OTHER CULTURES' GRAIN/FERTILITY GODDESSES written on the map of real craters and features and bright spots and scratches. this will be very tedious to duplicate with a log or sportive ball of some nondescript type like volley or basket.
Most of these grain goddesses' names are very hard to spell.

"Yumyum" is so far the only one I've memorized.

LPSC 2015: First results from Dawn at Ceres: provisional place names and possible plumes (The Planetary Society)
Posted By Emily Lakdawalla
2015/03/19 23:29 UTC

The bright splash crater is in the quad named Hobnil.

Dawn breaks over distant Ceres … and perhaps reveals signs of habitability (theconversation.com)
March 18 2015, 8.44am EDT

I’m not sure just how many of these there are, or how memorable their names will turn out to be. But as the Dawn mission’s principal investigator Chris Russell pointed out, there is one Mayan deity named Yum (Yum Kaax, god of agriculture and the jungle), who should readily be remembered. One can only hope the mission scientists find a suitably delicious feature on Ceres to give that name.

 

[marcus]

Om, thanks for posting the grid of Ceres named regions. Some pretty strange names. Every culture from every part of the world seems to have had a grain deity or fertility spirit. Happy Hobnil to you! Don't forget to celebrate YumYum day next Tuesday!

I'm trying to make sense of the current simview. It looks like Dawn has thrust turned off, and I see Canberra is assigned to Dawn but no signal.
It looks like as of 3Jun 15:50 UTC the altitude is right 4400 km and the speed is very nearly right 254 mph

and simview shows Dawn apparently approaching the S pole terminator which I guess it should cross early on 4 Jun UTC or like 6PM this evening pacific time (just a rough guess)

Simview is telling us that Dawn has arrived in Survey orbit on schedule as planned

Orbit    dates      altitude(km)  pixelsize(m) res/HST  period  soccerball at
RC3    April 23–May 9    (13,500)    (1,300)    24     15 days    (3.0 meters)
Survey    June 6-30      (4,400)      (410)     72     3.1 days    (1.0 meters)
HAMO    Aug 4–Oct 15     (1,450)      (140)     215    19 hours    (33 cm)
LAMO Dec 8–end of mission  (375)      (35)      850    5.5 hours    (8.5 cm)

Ready to start a mapping campaign on 6 June.
I guess they first have to verify that and measure all the fine details, so that would be what Canberra antenna is waiting to do.
EDIT :As of 8:41AM pacific, Canberra#35 is talking with Dawn!
https://eyes.nasa.gov/dsn/dsn.html
EDIT: Now as of 6PM pacific, Madrid #55 is talking with Dawn (it is 3AM in the morning there).
In simview Dawn seems to be just now crossing the Ceres S pole.

 

[OmCheeto]

...
ps. On a hopefully not true side note, I had an argument with someone at JPL a couple of weeks ago. I'm assuming it wasn't Dr. Rayman:

...

I think I've started another argument...

Peter Fries ‏@Peter_Fries Jun 2
@NASA_Dawn @b0yle Does Dawn have the capability to send back 'natural color' images?

NASA's Dawn Mission ‏@NASA_Dawn Jun 2
@Peter_Fries @b0yle yes, I can take data with which to make color images, but the team has not yet released any yet

OmCheeto 17 minutes ago
@NASA_Dawn @Peter_Fries @ridingrobots @b0yle I'm confused. http://blogs.egu.eu/geolog/2015/04/15/findings-from-nasas-dawn-mission-shed-new-light-on-ceres/ …

Have I totally lost my mind?

PIA19063 - Dawn's First Color Map of Ceres
This map-projected view of Ceres was created from images taken by NASA's Dawn spacecraft during its initial approach to the dwarf planet, prior to being captured into orbit in March 2015. Image Credit: NASA/JPL –Caltech/UCLA/MPS/DLR/IDA​

 

[OmCheeto]

Phew!

Hi [Om],

Sorry for my slow replies. Dawn keeps me busy, which comes as no surprise to you. We arrived in survey orbit this morning, and that will be tweeted and put on our mission status page.

You’re right that that was not I on Facebook. I mentioned about giving the information for tweeting. For Facebook, if they send a question back to me, I answer it, but most of the time they don’t. So I’m quite unaware of what gets posted there.

As usual, the topic is a little more complicated than it appears from what you quoted below. For the approach phase images, we used two different camera integration times (what most people call exposure times). One value was chosen to ensure Ceres was correctly exposed and the other was chosen to bring out the background stars. The images alternate, so we interpolate to get Ceres' location relative to stars. We did it the same way at Vesta. In at least one of the Ceres OpNavs, it just so happened that some stars showed up in the images exposed for Ceres. I don’t know what the Dawn person (who is not technical) had in mind with the comment about adding stars. We’ve never done that.

As for what Ceres would look like, you’re quite right that Ceres is significantly brighter than the background stars. That’s why we had two exposure values. I wrote in my March 31 Dawn Journal that Ceres’ mean albedo is about 0.09 and the Moon’s is about 0.12. So you’re also correct that the Moon’s is 1/3 higher. If it matters, remember that Ceres is farther from the sun. The Planetary Society reposts my Dawn Journals (as do some other sites), and sometimes (but not often), I respond to comments there. I did address this aspect of it in responding to a comment by Solon. That is, the intensity of the sunlight is around 12% at Ceres what it is at Earth or the Moon, so it would look darker to your eye. You’re also right that Ceres’ variation in albedo seems much lower, but, of course, there are those famous bright spots and others that are not so famous.

Regards,
Marc

I hope I'm not getting his staff in trouble.

On a trivial side note, I was curious at what distance Ceres would fully fill Dawn's framing cameras.
So I did some maths, and determined that it was around 3400 km.
It's a bit problematic, as Marcus pointed out that polar and equatorial diameters are a bit different: 891 & 963 km, respectively.

Field of vision    5.5°    vertical & horizontal (θ)
Field of vision    0.096 radians   
distance           3400    km   
1/2 field           327    km   tan(θ) * distance
full field          655    km   
1/2 diagonal        463    km   √ (2 * half field^2)
full diagonal       926    km   
polar diameter      891    km   96% of full diagonal
equatorial diam     963    km   104% of full diagonal

Close enough for government work.

 

[OmCheeto]

Oh. Wait. Peter said "natural color".
oops.

But as Dr. Ramen responded in the "comment by Solon" link referenced above:

DaGuz: 05/02/2015 06:07 CDT
Why no color pictures? The picture taken by Hubble showed the terrain was brown. The pictures released so far make Ceres look like our moon.

Marc Rayman: 05/04/2015 11:49 CDT
...
DaGuz: Most of our releases so far are only grayscale, but we have released maps based on our color data. Like the Hubble views, they are false color. We will release true color images as well. Ceres would look mostly gray (although darker than the moon).

hmmmm... Is it just me? What is it about people, that makes them ask to see full color pictures of a grey dwarf planet?

Ah ha! It's all Hubbles' fault. I distinctly remember that the images of both Ceres and Pluto were very colorful.
I wonder why they did that?

Ceres via the Hubble Space Telescope

Pluto via the Hubble Space Telescope​

Actually, I think I know why they do that. Never mind.

 

[marcus]

Om thanks for passing along the informative letter Marc Rayman sent you.
Today's Dawn Status report gives the latest news succinctly so I'll just copy it:
==quote http://dawn.jpl.nasa.gov/mission/status.html ==
2015

June 5, 2015 - Dawn Begins New Science Phase

As Dawn flew ... (4,400 kilometers) over Ceres’ north pole this morning, the spacecraft passed from the night side to the day side of the dwarf planet. That marked the beginning of the new mapping phase, and Dawn began taking photos and making other measurements on schedule. Circling Ceres every 3.1 days, Dawn will make extensive scientific observations when it is over the sunlit side and will transmit its findings to Earth when it is over the side in darkness. The pictures will be three times as sharp as those from the first mapping orbit. This mapping phase is scheduled to continue for eight revolutions, providing plenty of opportunities to gather a wealth of data.
==endquote, my emphasis==

 

[Janus]

The elevation map above inspired me.

First, here it is converted into a 3-D relief map:

And here I used it to create a rotating model of Ceres:

 

[OmCheeto]

The elevation map above inspired me.

First, here it is converted into a 3-D relief map:

And here I used it to create a rotating model of Ceres:

Sometimes, I get the feeling that NASA is stealing ideas from this thread...

Just released:

Fly Over Dwarf Planet Ceres
NASA Jet Propulsion Laboratory​

Published on Jun 8, 2015
A new video animation of dwarf planet Ceres, based on images taken by NASA's Dawn spacecraft , provides dramatic flyover views of this heavily cratered, mysterious world. The images come from Dawn's first mapping orbit at Ceres, at an altitude of 8,400 mile (13,600 kilometers), as well as navigational images taken from 3,200 miles (5,100 kilometers) away. The images provided information for a three-dimensional terrain model. The vertical dimension has been exaggerated by a factor of two, and a star field has been added in the background.
Category Science & Technology
License Standard YouTube License

 

[OmCheeto]

NASA's Dawn Mission ‏@NASA_Dawn 27 minutes ago
(2/2) A: Just started taking images in my new orbit. The team will share a new view of the bright spots soon. Stay tuned!

Yay!

hmmm... Actually, I'm more interested in the washed out slightly brighter than average spots now.

Argh...

 

[marcus]

The Fly-over digital animation YouTube is beautiful! "We used a three-dimensional terrain model that we had produced based on the images acquired so far," said Dawn team member Ralf Jaumann of the German Aerospace Center (DLR), in Berlin. "They will become increasingly detailed as the mission progresses -- with each additional orbit bringing us closer to the surface."

It looks just like cinematography, as if photographed. Was constructedl using 80 overlapping photos taken at 13500 and 5100 km.
having photos overlap, and digitized allows one to build a 3D digital model of the planet surface. (like stereo, basically using trig)
then from the digital model of the terrain they were able to reconstruct an image of the rotating landscape that looks completely natural.

Interestingly, they exaggerated the vertical scale by a factor of 2 so ridges twice as high, craters twice as deep. So you get a more vivid sense of the terrain.
Thanks for the link, OM!

 

[Janus]

Here I combined the relief map with the rotating globe to high light the elevation differences. it goes from blue-green for the lowest elevations to orange fro the highest elevations. I also shifted the lighting so more of the globe is lit, but you still get the shadow effect at the terminator.

 

[OmCheeto]

I'm afraid that I don't have the patience to be a scientist...

Another person on Facebook; "When will the first natural color photo of Ceres release?"

Me; "Ceres is about as colorful as Earth's moon."

 

[marcus]

You point out the need for patience, OM. For me this applies to the the infrared spectra. Because they should reveal things about the chemical composition.

I am not so impatient to see more detailed beautiful pictures of what the surface looks like to the human eye.
The human eye is a fairly limited instrument. I'm impatient to see reports interpreting the IR instrument readings. What IR wavelengths stand out? What elements and compounds do they signify?

The planetary imagery is not causing me so much suspense (though it will eventually yield answers about geological history.) What I'm wondering about are things like "how good are Dawn's instruments?" "how close does the probe have to get, to be able to tell anything?"
"how long do we have to wait before we hear some readings of the spectra? the really close orbit is not until December!"

And Marc Rayman, whether inadvertently or not, created more impatience by mentioning the IR instrument readings in the recent status report:
==quote http://dawn.jpl.nasa.gov/mission/status.html ==

June 8, 2015 - Dawn Conducts First Observations in New Science Phase

Dawn photographed Ceres and measured its spectrum in infrared and visible wavelengths as it orbited over the illuminated side on June 5 and 6. All measurements were completed as planned. When its orbit took to the night side again, the spacecraft pointed its main antenna to Earth and transmitted its findings.

Later this morning it will travel back to the day side and begin its second set of observations.
==endquote==

 

[OmCheeto]

You point out the need for patience, OM. For me this applies to the the infrared spectra. Because they should reveal things about the chemical composition.

I'm in no hurry. I keep thinking about how you've followed the mission from before it even lifted off, an tell myself to shut up.

I am not so impatient to see more detailed beautiful pictures of what the surface looks like to the human eye.
The human eye is a fairly limited instrument.

In some ways. In other ways, it is really incredible. From the "Why are there no stars?" question, it struck me as peculiar, that we can look up at the sky, and see the moon and stars, and the moon isn't super-saturated. Why is that? Drakkith and mfb posted some answers in a "Photons striking a camera sensor?" thread, but I couldn't figure out the answer.

I'm impatient to see reports interpreting the IR instrument readings. What IR wavelengths stand out? What elements and compounds do they signify?

The planetary imagery is not causing me so much suspense (though it will eventually yield answers about geological history.) What I'm wondering about are things like "how good are Dawn's instruments?" "how close does the probe have to get, to be able to tell anything?"
"how long do we have to wait before we hear some readings of the spectra? the really close orbit is not until December!"

And Marc Rayman, whether inadvertently or not, created more impatience by mentioning the IR instrument readings in the recent status report:
==quote http://dawn.jpl.nasa.gov/mission/status.html ==

June 8, 2015 - Dawn Conducts First Observations in New Science Phase

Dawn photographed Ceres and measured its spectrum in infrared and visible wavelengths as it orbited over the illuminated side on June 5 and 6. All measurements were completed as planned. When its orbit took to the night side again, the spacecraft pointed its main antenna to Earth and transmitted its findings.

Later this morning it will travel back to the day side and begin its second set of observations.
==endquote==

I don't know when it was, that I first thought; "Wouldn't it be cool if we could see the entire E-M spectrum!".
Of course, technology is doing that for us.

ps. There was another post today. I wonder if it is Dr. Rayman directing this ever increasing; "Let's put new posts in as many different places as possible, as Om is getting bored, and obviously likes a challenge".

Bright Spots Shine in Newest Dawn Ceres Images
June 10, 2015
...
The region with the brightest spots is in a crater about 55 miles (90 kilometers) across. The spots consist of many individual bright points of differing sizes, with a central cluster. So far, scientists have found no obvious explanation for their observed locations or brightness levels.

"The bright spots in this configuration make Ceres unique from anything we've seen before in the solar system. The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt. With closer views from the new orbit and multiple view angles, we soon will be better able to determine the nature of this enigmatic phenomenon," said Chris Russell, principal investigator for the Dawn mission based at the University of California, Los Angeles.
...

 

[mfb]

In some ways. In other ways, it is really incredible. From the "Why are there no stars?" question, it struck me as peculiar, that we can look up at the sky, and see the moon and stars, and the moon isn't super-saturated. Why is that? Drakkith and mfb posted some answers in a "Photons striking a camera sensor?" thread, but I couldn't figure out the answer.

The reaction of human eyes is also highly nonlinear. A camera needs tricks like multiple images with different exposure times to get the same range.

 

[marcus]

Om thanks for spotting that. The picture of the bright spots is considerably sharper and shows more detail than I had see before. I can understand Chris Russell guessing that the spots are reflection from ice.

Bright Spots Shine in Newest Dawn Ceres Images
June 10, 2015
...
The region with the brightest spots is in a crater about 55 miles (90 kilometers) across. The spots consist of many individual bright points of differing sizes, with a central cluster. So far, scientists have found no obvious explanation for their observed locations or brightness levels.

"The bright spots in this configuration make Ceres unique from anything we've seen before in the solar system. The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt. With closer views from the new orbit and multiple view angles, we soon will be better able to determine the nature of this enigmatic phenomenon," said Chris Russell, principal investigator for the Dawn mission based at the University of California, Los Angeles.
...

http://dawn.jpl.nasa.gov/news/news-detail.html?id=4619

If the spots are small ice-fields somehow pushed up from within then that seems even more interesting than that they might be dry salt flats. There are a remarkable number of them in just that one crater.
I see about 8 small separate speckles besides the two larger splotches.

 

[OmCheeto]

Om thanks for spotting that. The picture of the bright spots is considerably sharper and shows more detail than I had see before. I can understand Chris Russell guessing that the spots are reflection from ice.
http://dawn.jpl.nasa.gov/news/news-detail.html?id=4619

If the spots are small ice-fields somehow pushed up from within then that seems even more interesting than that they might be dry salt flats. There are a remarkable number of them in just that one crater.
I see about 8 small separate speckles besides the two larger splotches.

I'm now leaning towards salt flats...

...

Ok. I don't really care which it is. This is just freakin' fun!

 

[OmCheeto]

A few new images were posted yesterday:

Ceres' Southern Hemisphere in Survey

A large crater in the southern hemisphere of dwarf planet Ceres is seen in this image taken by NASA's Dawn spacecraft on June 6, 2015. This image shows many different surface structures associated with impacts.
This is among the first snapshots from Dawn's second mapping orbit, which is 2,700 miles (4,400 kilometers) in altitude. The resolution is 1,400 feet (410 meters) per pixel.
​

Ceres' Northern Hemisphere in Survey

...image taken by NASA's Dawn spacecraft on June 6, 2015​

VIR Image of Ceres, May 2015

Images from Dawn's visible and infrared mapping spectrometer (VIR) show a portion of Ceres' cratered northern hemisphere, taken on May 16, 2015. From top to bottom, the views include a black-and-white image, a true-color view and a temperature image. The true-color view contains reddish dots that are image artifacts, which are not part of Ceres' surface.
These images were taken at a distance of 4,500 miles (7,300 kilometers) from Ceres. They have a resolution of 1.1 miles (1.8 kilometers) per pixel.
The temperature image is derived from data in the infrared light range. The lightest areas are the hottest and the darkest are the coolest.​

 

[Dotini]

A few new images were posted yesterday:

Ceres' Southern Hemisphere in Survey

By casual inspection, the northern hemisphere seems to differ markedly from the southern hemisphere. I believe Mars and Vesta share this characteristic.

 

[mfb]

Craters all the way down.

The illumination seems to be different for the two images, so I would be careful with comparisons.

 

[OmCheeto]

The two upper pictures I posted this morning were from an altitude of 4400 km.
The other day I determined that the framing cameras wouldn't have full Ceres filling images until it was down to 3400 km.
Did I screw up my maths again, or are these cropped pictures? [I screwed up the maths]

[edit: corrected!]

Field of vision     5.5°    vertical & horizontal (θ)
1/2 Field of vision 0.048 radians
distance            6800    km
1/2 field            327    km   tan(θ) * distance
full field           653    km
1/2 diagonal         462    km   √ (2 * half field^2)
full diagonal        924    km
polar diameter       891    km   96% of full diagonal
equatorial diam      963    km   104% of full diagonal

hmmm...

6/6/2015 images
0.410    km/pixel
1024     pixels h&v
419.84   km h&v captured
927      km (Ceres average diameter)

It would appear that my previous calculations were off.
I will stop any further attempts at doing math.

I came up with 0.413 km/pixel for an altitude of 4400 km, so I'm sticking with my new numbers.

 

[OmCheeto]

More confusion. Dr. Rayman responded to my last email that I sent him:

June 4, 2015
Hi Marc,
...
As I suspected, everyone [here at PF] looked at the elliptical orbital graph you sent last time, and said it was “obvious”. I was of course, totally confused, as always.

[Om]

ps. I’ve started another argument, on Twitter this time……..

Peter Fries ‏@Peter_Fries Jun 2
@NASA_Dawn @b0yle Does Dawn have the capability to send back 'natural color' images?

NASA's Dawn Mission ‏@NASA_Dawn Jun 2
@Peter_Fries @b0yle yes, I can take data with which to make color images, but the team has not yet released any yet

OmCheeto 17 minutes ago
@NASA_Dawn @Peter_Fries @ridingrobots @b0yle I'm confused. http://blogs.egu.eu/geolog/2015/04/15/findings-from-nasas-dawn-mission-shed-new-light-on-ceres/ …​

June 12, 2015
Hi [Om],

I didn’t mean to confuse you with my plot. Never hesitate to let me know if I send you something unclear or unhelpful.

The image you refer to in your Twitter exchange is not natural color but rather false color. Dawn not only has the capability to take natural color images, but we released them for Vesta. So far, the only one we have released for Ceres is here but both the science camera and the visible mapping spectrometer can do this. It’s a surprisingly difficult process, however. Human vision is complex, and making natural color images is a little tricky. Still, we surely will release more.

Marc

I have just informed Marc that it is fortunate for him, that I am surrounded by the smartest people in the universe, here at PF.
I also asked for clarification on his response:

When you say the image is “false color”, do you mean the colors aren’t real, or are they real, but just over-saturated?

 

[OmCheeto]

For the record, I warned him, to not continue, to correspond with me...

Hi [Om],

On Dawn (and in general) false color does not mean oversaturated. Rather, certain wavelengths in the original data are assigned different (you could even say false) wavelengths in the picture. As an example, you might have data on a scene in near ultraviolet, red, and infrared. We can’t even see the first and last of those, so it would look black to us. But we can synthesize an image in which we assign the near ultraviolet data to, say, blue. That’s false, and in fact the real scene might look different in blue light, because the materials reflecting the light have different optical properties in blue light from ultraviolet light. Similarly, the other wavelengths may be given different colors. That’s OK. We label it as false color and never pretend it is anything else. We might assign the actual red wavelengths to green and the infrared wavelengths to red. So, now we have views in blue, green, and red, and we can construct a picture from that. It’s colorful, but it’s false color.

Some observations may be conducted at wavelengths that have special meaning. In astronomy, for example, one might measure the wavelength at which certain interesting atomic species emit radiation. It might be near the visible or it might even be far away. It could be gamma ray, X-ray, UV, IR, microwave, etc. Measure several of those, put them together with false color, and it’s a convenient method to see where the action is that you’re interested in.

It can be more complicated. Sometimes the false colors don’t correspond to any wavelength range in the original scene. The choice of the colors is usually meant to help our eyes pick our salient features. In some cases, it is more powerful to assign ratios of colors in the original data to individual colors in the final image. (Ratios of reflectivity at different wavelengths can be very diagnostic of certain mineral types.) So, for example, you might take the ratio of infrared to green and assign that to blue. If the ratio is high (much more IR than green light reflected from the object), it would be bright blue. If the ratio is low, it would be dark blue.

In all these cases, it is the underlying quantitative data that tell the real story, but the false color images help guide us to the interesting places. As visual creatures, such imagery can be very useful.

I hope that’s helpful.

If I had more time, I might enjoy the physics forum. I have wide ranging interests. All my degrees are in physics, and I greatly enjoy cosmology, astrophysics, particle physics, laser and atomic physics, relativity, and more. Working on a planetary mission is great fun, but my principal scientific interests lie elsewhere. Alas, Dawn keeps me much too busy to follow any popular discussions, much as I enjoy communicating with the public and sharing interesting ideas.

Marc

I don't know about you all, but I have the best pen pal in the world.

 

[OmCheeto]

But then, I yelled at him;

in the future, instead of using the term; “enhanced colour view”, could you say; “trans-human compressed electromagnetic spectrum view”.​

I have no idea why he continues to correspond...

 

[OmCheeto]

The reaction of human eyes is also highly nonlinear. A camera needs tricks like multiple images with different exposure times to get the same range.

After 7 days of study, I think I've figured it out. At the most basic of levels, of course.
I had to re-read Dr. Rayman's last email at least 5 times before I could understand what he was trying to get across.
Unfortunately, I responded after reading it only once.
But fortunately, after re-reading my response, it appears that I did not let on that I didn't really fully understand what he was saying.

I also re-read Drakkith's response in the CCD thread, and your reference. After accumulating much needed missing data, those responses too made sense.

As Mr. Spock would say; "Fascinating..."

 

[OmCheeto]

No, please don't do it! Not the obelisk!

Still no obelisks. But they did find a pyramid.

NASA's Dawn Mission ‏@NASA_Dawn 11 hours ago
A "pyramid"-like feature stands out in today's #Ceres image http://go.nasa.gov/1GP9ogi​

I'm guessing this is what they are talking about.

It looks more like a "limpet" snail to me. hmmm... They can call it Mt. O'Limet.
In a later tweet, they claim it is 5km (3 miles) high.

Is this our first mountain?Interesting "fracture" structure in the bottom left hand: