venus 32k/64k

[Malenfant]

But I expect that every good scientist should listen to what others have to say, regardless of their standing.

You would be surprised how long the list of people is even in this forum whose opinion I value VERY much. A number of them are no (natural) scientists at all.

Then it should be obvious to you that one's ability to do science or even to have a valid opinion on a scientific or related subject is not based on whether one has a PhD or MSc or anything else. So quite why the first thing you did is to point out that Mr Mitchell does not have a PhD and then claim that this validates your opinion of his work is beyond me.

It is correct that you are not among them. But this should not be surprising, given our longstanding "love affair".
But you might be surprised, I am spending quite some time reflecting why you are behaving against me as you do . I think I am getting closer these days

I don't know why you have to think about it, I've often told you exactly what it is about you that I find so offensive... but since you never listen to me, it seems pointless to explain why again.

But you see, you don't value my opinion on anything simply because you think I'm not worth listening to, based on your own personal bias against me. But even though I don't like you, I'd still put the same weight on your opinion as I would anyone else's. And if I had a question regarding your specific field of expertise then obviously I'd still hold your opinion higher - because what you know is not related to who you are. The message is what's important, not the messenger, and that's the difference between you and me.

[chris]

But then we agree from the start and could have saved our time!! I always said these pictures look nice, notably with a glass of beer, but they have ZERO scientific value.

That's indeed correct, since the guy just fills in empty slots at will to make the images look NICER.

The intent of the reprojected images is clearly to give some idea of how the Venera landing sites would appear to a human visitor. Given the gaps in the data, some license must license must be taken in the reproduction. It would be nice if the site also had reprojected images with blank areas instead instead of cloned pixels, so it was evident exactly which areas are based on actual Venera data. But even without such images for comparison, the reprojections are useful--with the original projections, it's much harder to understand what we're looking at. Simply knowing that originals are spherical projections helps somewhat, but not as much as actually seeing the reprojected images. I understand that the spherical projection is adequate for many purposes other than visualizing the larger scale geography of the site.

And incidentally, unless explicitly stated, one tends to loose every credibility with such methods. And a guy who tacitly fakes data ONCE, will do that uncontrollably again at other places...Why should I believe that the same guy did not manipulate --equally tacitly-- the color shades in the respective images. Or as I said, perhaps the data were not complete and the missing rest was phantasy. Why should I believe anything now??

Don Mitchell makes no secret about cloning the data; he's not "tacitly faking data." The fact that he produced those images in no way invalidates his other work, which seem to me to be a careful recovery of the original data. The science of image processing has advanced greatly since the Venera landings, so there is potentially a lot to be learned by revisiting this old data. Some months ago, I was following this thread about Don's Venera work on unmannedspaceflight.com:

http://www.unmannedspaceflight.com/inde ... =2712&st=0

It's a fascinating discussion, with participation (and praise) from working planetary scientists like Phil Stooke (whose small body maps are used in Celestia.) There's some explanation of details that were missing from the original reproductions of the Venera images. It's also clear that Don has sought the advice of original Russian space scientists in his Venera project. It's because I have such a regard for his work that I'm continuing this debate at all. I think he would be a good person to seek for advice on Celestia's visual realism.

--Chris

[t00fri]

Well, I cannot share such a view, unless it is clearly stated e.g. under each affected figure that "artistic freedom" was used. Another grave point of criticism I have is that his Website superficially has the appearance of a scientific report, but it is not clearly stated throughout what is his own contribution and what data were released by the Venera mission teams.

As I said, he may be very good at computer graphics but that is a priori an entirely different issue from /scientific/ analysis. It's two very different professions, each with its own professional rules.

I have never claimed that his graphics work was not useful. I personally enjoyed the images, for example. It may be useful for all sorts of things, notably educational. Yet it is rather worthless in the sense of a reliable scientific analysis, where usually the analysis of the inherent uncertainties is among the most important task. That was largely what I was concerned with in this particular discussion. I have also clearly stated this aspect repeatedly.

Bye Fridger

[Malenfant]

Hm, this poses a quandry for Fridger doesn't it . I've been supporting Mitchell's work here, but my opinion doesn't count for anything in Fridger's mind because apparently I'm not worth listening to. But Chris is also supporting his work too, and Fridger does listen to him. And other professional planetary scientists have piped up in support of him elsewhere too.

How about it, Fridger - are you actually going to be willing to admit you're wrong about something for once? And don't you think we could have saved a lot of time and energy here if you'd just listened to what I said in the first place? Because you know, maybe my opinion is actually informed about some things (heaven forbid that I should be expected to know anything about Planetary Science after all, given my background).

And Chris, thank you for showing a reasoned, rational and informed assessment of Mitchell's work. It's a pity that our resident "professional scientist" couldn't do the same.


EDIT: Oh never mind. I guess Fridger still thinks he's right about everything after all...

[Malenfant]

I have never claimed that his graphics work was not useful. I personally enjoyed the images, for example. It may be useful for all sorts of things, notably educational. Yet it is rather worthless in the sense of a reliable scientific analysis, where usually the analysis of the inherent uncertainties is among the most important task. That was largely what I was concerned with in this particular discussion. I have also clearly stated this aspect repeatedly.

First, you haven't stated this clearly at all. You did, however, make it very clear that you had dismissed his work based solely on his personal background.

Second, nobody ever claimed - anywhere on this thread - that this was even anything to do with 'reliable scientific analysis'. The whole reason I linked to that site was to show that work had been done to generate realistic colour images of Venus' surface from the Venera lander, that could potentially be used to colourise a Venus texture in Celestia. That's it.

For some reason though (apparently based on your own perception that the website was supposed to be a scientific report, which it isn't), you decided that because of the man's background, and because he didn't have a PhD in astrophysics, and because he'd used Photoshop to fill in some gaps (admittedly naughty of him), the entire body of the work that he did was (a) completely useless and (b) scientifically invalid. And then you started going on about how the whole lot was "bad science", and just art. NONE OF WHICH IS REMOTELY RELEVANT TO THE REASON WHY I LINKED TO THE SITE HERE.

I thought - foolishly perhaps - that it could be a useful reference to colourising Venus' surface, given the clearly vigorous effort that was being made to use correct photometric and colour corrections by the author (which again you chose to dismiss out of hand). I didn't say a damn thing about using ANYTHING on that site for "scientific purposes" at all. Instead, you just ruthlessly attacked the guy based on your own completely irrelevant agenda about its scientific validity, and your own baseless assumptions about his motives and background. And still you stubbornly insist that you're right when you're not.

I think your actions and attitude here really speak for themselves, Fridger. And that is all I have to say about it.

[chris]

Let's cut out the ad hominems and focus on the topic of images of Venus.

--Chris

[ElecMoHwk]

I'm still wondering if these 32K/64K tex's are available in Zip files?

[RVS]

I'd like to make a note.
I am working in the area, unrelated with space exploration (dynamics of fluids), but I know, that there in Soviet Union many things was classified absolutely without necessity, buried somewhere in archives and then lost. The original data of soviet space probes are in the best case very difficult to find. (However the resent loss of Apollo tapes by NASA is somewhat similar). And the official scientific approval of the modern treatment of photos is difficult to obtain, because the project is finished decades ago.
In May Don P. Mitchell published his reworked photos of Venus?€™s surface on the forum of periodical 'Novosty kosmonovtiki' ('News of space flight'). This is quite serious place, visited not only by many enthusiasts, but by actual specialists too. The reaction of user Vladimir (as far as I understand, he is a space engineer, participated in the Venera program as spacecraft manager): ?€?Don! Although I was one of the first to hold this panoramas in hands, I am shaken by new and absolutely unexpected perspective. Thank you.'

[t00fri]

Chris, Malenfant,

after so many things have been said and unfortunately misunderstood in part, let me try to summarize once more the issue that I for my part was/am concerned about. I will do that mostly by quoting from my own posts to make clear that my concern has NOT changed in any way throughout the discussion.

Also clearly it is NOT the matter of being right or wrong as concerns myself.

Since decades I have been involved in peer-reviewing for the world's leading scientific physics journals. I think I do have all qualifications to judge the scientific value of such presentations from a senior physicists perspective.

Right from the beginning of this discussion, I asked about the scientific value of the existing information.

I was of course aware of the Venera landers (never claimed there was
no landing on Venus). But I don't know what scientific value some color remastering by a guy on a site with the "inspiring" .com name

" www.mentallandscape.com"

has ...

+++++++++++++++++++++++++++
NOTE: This question does NOT interfere in any way with possible usefulness of the material for popular illustration/motivation/education purposes, of course.
+++++++++++++++++++++++++++

I then clearly confronted the situation with that of Titan, where I was given the respective official publication in the acclaimed scientific journal "Nature" by the Cyclops lead scientist, after much useful communication with him about the (astro)physics background.

This should have become clear in my response to Spiff:

After the Soviets spent lots of money & effort to get to Venus, they also must have had an interest to publish their solid scientific results on behalf of the Venera mission in accepted international journals!

30 years ago, they have certainly done so already in my field of particle physics!
[Edit: I have attended in this time window quite a number of international conferences in different locations of the Soviet Union, without major difficulties to enter and move around!]

Therefore, I want to see the original publications containing these potentially very important color images.

It is just a ridiculous thought to imagine that only a few space artists managed to evaluate and publish their GREAT color imaging data!!!

If the lead scientists from Venera believed these images to be reliable, they would have pushed to get their names out on respective papers. You BET!

Where are they??

Again it is obvious that my essential concern is about the scientifically valid information available. Personally, I care little about popular level imaging that I could do myself if I so wanted.

I emphasized the different aspects involved explicitly to Chris:

please understand. There are different levels on which one may argue.

When I am with my beer at night, I am certainly a vivid admirer of space art and anything else that looks exciting in this domain

But when it comes to the potential evaluation of /important/ scientific claims --and such color images of Venus ARE important-- then I am turning into the professional scientist that I am since decades!

And on that scale, only "bona fide" published results can be considered seriously. Could you imagine that I cite a Website in my next paper?? Come on...

Any one of my senior colleagues worldwide would judge about this matter in the same way.

Since I was only concerned about the scientific value of Don Mitchel's work, I then had a look at his professional profile. There was no PhD in physics/astrophysics/planetary science/... mentioned, but instead:

From his picture he seems definitely below 40, say. He calls himself a "retired research scientist" with professional experience at Bells lab and Microsoft!
...
Such a career is not of the kind where I blindly believe what I get to read, when it comes to scientific results.

There is no need to emphasize that reliable, truely scientific analysis of such complex, old mission data need far more proven planetary/experimental physics experience. A previous software job at Microsoft at best underligns his experience with computing!

If he had instead provided a list of scientific, refereed papers on his Website, I certainly would have read those instead. I would have been able in that case to form a more solid scientific opinion.

Finally, let me make clear a crucial subtlety: Sure enough people without proven professional qualifications as scientists may possibly also do valuable and interesting work related to science. Notably in connection with computing.

But the respective scientific value is usually hard to asses, since the specialized training and experience in highly qualified research teams of institutions with proven reputation was lacking. Also previous jobs at good places help to asses people's qualification, since with each new job the applicants went through careful professional screening of their specific qualifications...

NOTE: For postdoc and faculty job applications of scientists at virtually all decent research institutions in physics worldwide, ALL publications that have NOT been peer-reviewed are ignored.

It is unavoidable that evaluation of the scientific value of some such work, is largely also a matter of confidence in the qualifications and the working philosophy of the person concerned. The only alternative would be to redo the same analysis and compare. That is clearly impractical in practice! That's why previous formal qualifications and proven experience play a crucial role virtually in case of every institution, company etc.

Scientific analysis/work is concerned with extracting TRUE results from Nature. Because of that, usually the hardest part of scientific work relies in a careful estimation and publication of inherent uncertainties etc. Also "limits of knowledge" must be clearly exhibited!

That part makes up for the greatest difference to work of more popular interest, including work for educational purposes.

+++++++++++++++++++++++++++++++
I sincerely hope that this summary of my point of view, along with comments on some generally accepted aspects of scientific working, was useful to some extent.

In this discussion, my primary concern has been the important question of existing scientifically reliable (color) information about the surface of Venus!. This question does interfere little with issues about the possible usefulness of the existing material for popular illustration/motivation/education purposes.
+++++++++++++++++++++++++++++++

Bye Fridger

[jdou]

So, what colour could be Venus to respect all your "point of view"?

[Malenfant]

Since decades I have been involved in peer-reviewing for the world's leading scientific physics journals. I think I do have all qualifications to judge the scientific value of such presentations from a senior physicists perspective.

That's great... if this was a scientific paper presented to a Journal. But it isn't, so your experience isn't particularly relevant here. You do not have a monopoly on ability to judge the scientific value of anything here. And whether you're a 'senior physicist' or not is irrelevant. I've worked in planetary science itself and have also reviewed a couple of papers in my time, so I know exactly how the process works. But since you don't "value my opinion" you ignore it and so you have wasted everyone's time here and caused a lot of friction because of your attitude.

Right from the beginning of this discussion, I asked about the scientific value of the existing information.

Which is not relevant to the current discussion at all. When I posted the link, I said:

You're wrong, Fridger - we do have some colour images of Venus. I'm surprised you forgot about the Venera landers... there's some very good remastering work done here on them:

That's all. I didn't mention anything about its scientific quality at all, the only purpose for me presenting that link was to show work that was already being done. (which as Chris pointed out has already been examined and praised by other working planetary scientists who again know more about this subject than you do).

If this had been presented in a science journal, then you'd be more justified in your criticism. But it isn't.

I was of course aware of the Venera landers (never claimed there was
no landing on Venus). But I don't know what scientific value some color remastering by a guy on a site with the "inspiring" .com name

" www.mentallandscape.com"

has ...

This is where you showed your true colours, of course. The first comment you made here reveals that you immediately dismiss Don Mitchell's work simply because it was presented on a website with a name you didn't approve of.

+++++++++++++++++++++++++++
NOTE: This question does NOT interfere in any way with possible usefulness of the material for popular illustration/motivation/education purposes, of course.
+++++++++++++++++++++++++++

THEN WHY THE HELL DID YOU RAISE IT AS A POINT HERE THEN.
The ONLY reason I mentioned this site was because it was useful for illustration/educational purposes, and that is what Celestia is. It's a visualisation tool, not a bloody science paper.

Therefore, I want to see the original publications containing these potentially very important color images.

It is just a ridiculous thought to imagine that only a few space artists managed to evaluate and publish their GREAT color imaging data!!!

If the lead scientists from Venera believed these images to be reliable, they would have pushed to get their names out on respective papers. You BET!

Where are they??

Come on Fridger, even NASA doesn't process everything immediately after it's received. European scientists were doing original processing on Magellan data to extract altimetry data over ten years after the mission started sending back data (I know, I worked with some of them). I myself was working on Voyager data which for 18 years hadn't even been released with the correct camera pointing data attached til I specifically looked for it and added it myself.

Again it is obvious that my essential concern is about the scientifically valid information available. Personally, I care little about popular level imaging that I could do myself if I so wanted.

Bully for you. But again, the scientific validity of this work is not the issue. The issue was whether the colour work was usable in Celestia. And Celestia is not a science journal and should not be held to the same standards. We want realism in Celestia, but that doesn't mean we should close the doors to valid extrapolation from existing data.

Since I was only concerned about the scientific value of Don Mitchel's work, I then had a look at his professional profile. There was no PhD in physics/astrophysics/planetary science/... mentioned, but instead:

From his picture he seems definitely below 40, say. He calls himself a "retired research scientist" with professional experience at Bells lab and Microsoft!
...
Such a career is not of the kind where I blindly believe what I get to read, when it comes to scientific results.

There is no need to emphasize that reliable, truely scientific analysis of such complex, old mission data need far more proven planetary/experimental physics experience. A previous software job at Microsoft at best underligns his experience with computing!

Again, this is entirely irrelevant, and once more shows that you're more concerned with the person who is presenting the data than the data itself. Don Mitchell's background - or anyone else's - is irrelevant to the quality of his work, which has been well-documented on his site. But you just dismiss it once more because you don't care about the data, just the author.

Finally, let me make clear a crucial subtlety: Sure enough people without proven professional qualifications as scientists may possibly also do valuable and interesting work related to science. Notably in connection with computing.

How very magnanimous of you.

But the respective scientific value is usually hard to asses, since the specialized training and experience in highly qualified research teams of institutions with proven reputation was lacking. Also previous jobs at good places help to asses people's qualification, since with each new job the applicants went through careful professional screening of their specific qualifications...

NOTE: For postdoc and faculty job applications of scientists at virtually all decent research institutions in physics worldwide, ALL publications that have NOT been peer-reviewed are ignored.

It is unavoidable that evaluation of the scientific value of some such work, is largely also a matter of confidence in the qualifications and the working philosophy of the person concerned. The only alternative would be to redo the same analysis and compare. That is clearly impractical in practice! That's why previous formal qualifications and proven experience play a crucial role virtually in case of every institution, company etc.

Absolutely none of this has any relevance to this thread. You're not interviewing for a job position, you're looking at some pictures on a guy's website.

Scientific analysis/work is concerned with extracting TRUE results from Nature. Because of that, usually the hardest part of scientific work relies in a careful estimation and publication of inherent uncertainties etc. Also "limits of knowledge" must be clearly exhibited!

He's documented every step of the process, albeit not all in one place. And yes, he should have left the data gaps untouched and not filled them with cloned data for those perspective images. But again, those perspective images aren't even relevant to any colour discussions, I just showed them because I thought they looked impressive. I certainly didn't expect that you would launch into a baseless personal attack on the credibility of the author of those images.

+++++++++++++++++++++++++++++++
I sincerely hope that this attempt to summarize my point of view has helped a bit to make clear what my concern has been in the important question of existing scientifically reliable (color) information about the surface of Venus!
+++++++++++++++++++++++++++++++

And it's already been shown that people whose opinions actually matter (i.e. working planetary scientists, not some random astrophysicist who knows little about the field) have already looked at and discussed Don Mitchell's work elsewhere and approve of it. I'd hold their opinion as being more important than yours, and the only criticism you've made here has been of Don Mitchell himself, based on your own baseless assumptions about his motivations.

In short, Fridger, your entire discussion here has been largely irrelevant and unnecessary. Not once have you actually produced some definitive criticism of the colour work that Don Mitchell has done - you've made some statements based on assumptions, but you've not demonstrated anywhere how his work is actually flawed. All you've done is wasted everyone's time, as usual.

And frankly, this is the best we're going to get. This is the only data we have, and he has been using all the tools available to him. If this doesn't satisfy you, then nothing will.

[Spaceman Spiff]

OK, I see this post is now infected by another bout of "cannonballunstoppabilis-wallusimmoveabulis-itis" and so I'll repeat my points to honour Chris' request to get back to the issue of the Venus texture.

However, in passing, and for the information of all, I must respond to Fridger, but I put this into a topic in Purgatory: Why Soviet Space Missions like Venera suffered. (http://www.celestiaproject.net/forum/viewtopic.php?p=81731).

The Venus global texture is properly black and white because it is a single band, single polarimetry SAR (radar) image.

Any similar texture that has an orange colour is the B&W SAR mosaic colourised to match Venus sky colour as typically seen from the ground by Venera probes (Magellan never measured this, only Venera probes). The orange overcast colours the ground, just like on Titan. Note Fridger's Titan texture is also colourised.

Any colour (or non-monochrome) Venera ground image cannot be used to extrapolate colour over the entire global texture.

So, fulfilling Daniel J's request for a colour Venus global texture is not possible - it doesn't really exist.

By the way, future development: it would be sensible to keep the global texture B&W and let a computed sky colour 'colourise' the ground in celesita. Colourised albedo textures might stop this.

Cham - well spotted, but that's a matter of 'shape' not 'colour.' Anyway, Don Mitchel states the 'jailbar' pattern of Telemetry interruptions across each image is filled in by a fractal extrapolation pattern - it's 'made up' (but not arbitrarily). It still doesn't change the colour data. I think the (one) colour photo is from the Soviets themselves, not Don Mitchel, because I remember seeing it on the Beeb's "The Sky At Night" years ago.

Spiff.

[Malenfant]

I think we can make some very educated guesses as to what colour Venus' surface actually is (and note, I'm just talking about the surface, not any reflected tint from the atmosphere).

We know that most of the surface is volcanic plains, made of basaltic rock, which is generally black or dark grey in colour.

From the look of the Venera pictures, texturally it's not too disimilar to lava plains on Earth. We know that there are regions that are smooth (radar dark) and rough (radar bright). The smooth regions are probably like what is in the righthand image in the perspective view, or the runny pahoe'hoe flows seen in Hawai'i on Earth. The rough areas are probably more like A'a flows on Earth, with big blocky lumps of rock. We know there are "pancake domes" which appear to be extrusive features made of thicker,more viscous lava. Crater ejecta regions on Venus are radar bright, most likely because of the rocks and boulders blasted out by the impact. We also know that mountain tops are radar-bright too, but this is thought to be because of radar-reflective minerals precipitating out there (pyrite frost, etc) so we can assume that those regions have a metallic sheen to them.

I think there's enough info there to create appropriate colours for Venus' surface. We can use volcanic plains on Earth as a start - particularly new flows around the eruptive centres of Hawaii, which are comparatively untainted by vegetation and erosion. Sure, it's conjectural but it's based on facts that we know about the surface from Magellan and Venera. And so far this is as good as it's going to get.

[t00fri]

Spiff,

...
The Venus global texture is properly black and white because it is a single band, single polarimetry SAR (radar) image.

Yes that was my starting point.

Any similar texture that has an orange colour is the B&W SAR mosaic colourised to match Venus sky colour as typically seen from the ground by Venera probes (Magellan never measured this, only Venera probes). The orange overcast colours the ground, just like on Titan. Note Fridger's Titan texture is also colourised.

True. The essential difference to the Venus case from a more scientific point of view is that in case of Titan we have excellent and detailed publications to read precisely about the detector equipment used!

So, fulfilling Daniel J's request for a colour Venus global texture is not possible - it doesn't really exist.

That's precisely what I wrote to him

Daniel,
...
As to Venus colors, please remember that there are NO color photographs from the Venus surface! The data that John is using are RADAR data, I suppose.

So why are you complaining about missing color, although nobody knows what colors we shall have down there? You should know meanwhile that Celestia is not trying to present "phantasy" in its more serious add-ons, at least.

By the way, future development: it would be sensible to keep the global texture B&W and let a computed sky colour 'colourise' the ground in celesita. Colourised albedo textures might stop this.

Knowing about the Titan ground photo, my Titan coloration in the Celestia distribution has been done in exactly this spirit!

Spiff, did you notice that photo with Russian text that I quoted from "Don Davis' "archive"?

http://www.donaldedavis.com/BIGPUB/V14COLR.jpg

It refers to Venera 13 & 14 and looks pretty "professional" to me, including the visible color gauging bars ...But I seem to rember that you mentioned that already?

Cheers,
Fridger

[Malenfant]

As to Venus colors, please remember that there are NO color photographs from the Venus surface! The data that John is using are RADAR data, I suppose.

Again, this is simply 100% false. There ARE colour images of Venus' surface, taken from Venera. The work that Don Mitchell has done on that is valid. The fact that you choose to reject them is irrelevant, they're still out there.

There is no global true colour map of Venus of course, but of specific locales (around the landers) we do have colour images, whether you like it or not. So stop trying to insist that they don't exist when they clearly do!

So why are you complaining about missing color, although nobody knows what colors we shall have down there? You should know meanwhile that Celestia is not trying to present "phantasy" in its more serious add-ons, at least.

First, it's spelt "fantasy", not "phantasy".

Second, as I said, we have a pretty good idea based on the rock types what sort of colours we're likely to see. I'd much rather see a texture based on educated guesswork and extrapolation (and clearly marked as such, obviously) than have nothing at all because of one person's insistence on using only peer-reviewed data (which in this case isn't even available).

[t00fri]

Merriam Webster:

Main Entry: 1fan?·ta?·sy
Variant(s): also phan?·ta?·sy /'fan-t&-sE, -zE/

Britannica.com

fantasy:
also spelled phantasy imaginative fiction dependent for effect on strangeness of setting

[Malenfant]

imaginative fiction dependent for effect on strangeness of setting

I think it is very obvious that colourising a texture of Venus based on existing knowledge about the rock types on its surface that are extrapolated from in-situ sampling, imaging from the surface, and radar reflectivity does not even remotely fit the above description.

Get some perspective, Fridger. Just because something is not based on peer-reviewed work does not make it "phantasy" (which is at best a pretentious version of the word that nobody ever uses in practice)

[John Van Vliet]

--- edit ---

[t00fri]

hey hey John,

I suppose your were a bit surprised what happened in your thread meanwhile?

Bye Fridger

[John Van Vliet]

--- edit ---