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Mars:

The colors of the sky of Mars, the very true images:

Summary of the previous episodes:

When I submitted my position - the sky on the surface of Mars is probably not red but rather blue - objections were sometimes raised. I gave my answers to these objections elsewhere, but as clearly the objections which I already answered are rehashed endlessly by impatient readers, I will briefly answer again these objections, before tackling the question under an angle still different from those which I already approached. Some of these objections appear completely naive or absurd or quite simply ridiculous, they were however actually opposed to my articles.

I must stress that these are summarized answers to these objections. For more detailed arguments, you need to read my other, previous pages, on this topic.

The core of the issue:

First of all, I was often told that I presented "my" images of Mars and not the true images of Mars, those taken by the NASA cameras. The idea here was to more or less imply in more or less diplomatic terms that I was faking the images, and that if anyone would check my fakes against the original NASA images (the raw data), one would immediately see that the Martian sky is not blue but red. In this presentation, I give the answer on this.

Then, I was told that it is acceptable that the color balance at the time of the Viking missions (1977) may have been approximate or incorrect, because digital imagery was then stammering, but those images taken more recently by the Pathfinder mission benefited of important technical progress realized since then, and thus do not allow such doubts any more: the Martian sky is really red. In this presentation, I also answer this.

How to get the "real pictures" of the surface of Mars:

You just need to ask NASA for it. Here are the steps.

NASAview:

The first thing to do is to download the NASAview software. It is a piece of software (one EXE file, no DLL, no risks for your PC) making it possible to view the photographs I discuss here, since they are in a particular format called "PSD" (Planetary Data System) and not in some standard format such as Bitmap or Raw. Without this viewer program, you will not be able to view these images. With this program, you will be able to see them, but also to convert them into other formats, by screen printing and pasting them as new images in your usual graphic software.

You will find the download page for NASAview on http://pds.jpl.nasa.gov/license.html, it is enough to indicate you name and email address to get it, it does not require payment to download it. The license of use is free. This license means that you only have the right to use the software, and no right to sell it etc. There are versions for Sun Solaris, for all the versions of Windows, and for Mac OS.

Ordering the images:

The images can be ordered from http://pds.jpl.nasa.gov/cgi-bin/vlsearch.pl?FIRST

You will find two CD-Rom discs of images taken by the Viking I and II landers, and three CD-Rom discs of images taken by the Pathfinder lander. The prices are moderate. I received all 5 CD-Rom discs and their accompanying mails I ordered online (secured online payment by credit card) by mail within ten days:

The two Viking image volumes.
The three Pathfinder images volumes.

The 5 CD-Rom disks I ordered are:

The CD-Rom discs are well organized in well documented subfolders, with an HTML image browsing system showing the images reduced to GIF formatted thumbnails, with explanatory texts. As explained above, it is necessary to use the NASAview viewer program to open the real images.

You can forget the "Pathfinder" discs: they quite simply contain no color pictures. The Viking discs on the other hand offer a certain number color images.

You will have to assemble by yourself the separate images (RGB) to reconstitute each color image. It is not very practical, but this collection is really the "raw" images taken by the Viking cameras, they are intended rather for researchers than for the general public.

For example, you will find in repertory \A00XX of the CD a large number of files, including these three: 11A038.BLU, 11A038.GRN, 11A038.RED. 11A038.BLU is a black and white image which contains the blue component, 11A038 contains the green, and 11A038.RED contains the red. They thus should be "RGB combined" to create the color image.

To assemble these images, open each of the three raw images, the red, the green, the blue, with the NASAview software.

For each image, do a screenshot, crop the screenshot exactly at its border, record each screenshot in Bitmap format (BMP) with your usual graphic software. Do not mix the names you use for the three files! Use a convention such as this:

11A038.BLU becomes 11A038blue.BMP
11A038.GRN becomes 11A038green.BMP
11A038.RED becomes 11A038red.BMP

Then, open these three bitmap images with a graphic software allowing to combine images of separated color components into a single new color image.

I used the excellent it Paint Shop Pro 6 for that, it can carry out very simply the RGB combination without any complicated manoeuvers. It is enough to choose "Colors" "Channel combining", "Combine from RGB" and to point at the three images. The software combines the three RGB images and creates a new image showing the resulting colors.

So what do these infamous color picture show, in the end?

The show the blue sky of Mars:

12A045

Image 12A045 from CD #1.

I repeat, all these images show the blue sky.

The image that I publish above is an image that you never saw in any magazine. The reason is quite simple: it is afflicted with erroneous pixels. NASA, the Press, books, magazines, all prefer to publish images of good quality.

I repeat, all these images show the blue sky.

This image is not an exception among a mass of other picture showing a red sky. The other pictures also show a blue sky, except for those which are very dark because they were taken at dusk or dawn or in the night. On these images, the sky is dark. Dark or black blue, not dark red, actually.


Appendix: answer to predictable future questions about the above:

"Can you send me all these images of NASA CD-Rom discs?"

"The image that you show has some strange defects. What did you alter?"

"You show only one photograph. What do you hide about the others?"

"These are Viking pictures. What about those by Pathfinder?"

"The links you provide do not even function, therefore what you claim here is false."

"You really believe that NASA has nothing better to do than paint Mars in red?"

"The Spirit Robot is now, in January 2004, sending Mars color pictures and the sky is red."

A mistake explains why the Spirit and Opportunity images were much too red:

February 13, 2004:

Jim Bell declared in an interview in the New York Times that if the images taken by the Spirit and Opportunity rovers appear so reddish and even dark red, it is because a red filter had been activated due to an error of unknown reason on the camera of the two robots.

Jim Bell is a well-known astronomer, specialized in planetology, dealing among other things with the image processing of the Hubble space telescope, he is also the person in charge for the setup of the panoramic cameras of Spirit and Opportunity missions.

Bell speaks on a "huge mistake" and a "terrible mess."

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This page was last updated on January 10, 2003.