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Archive for the ‘Mars’ Category

The Religion of the Face on Mars

Wednesday, July 2nd, 2008
Email about the Face on Mars
Email about the Face on Mars

A few days ago I received the email shown above from a person in Italy. Note that I have slightly cropped the images to fit the space available here. I assume that this email was directed to me because of my previous writings that the so called “Face on Mars” is nothing more than a mesa. In the email I’m not sure if they’re referring to the Face on Mars as a miracle or if the writer is being sarcastic and referring to the subsequent images as miracles of deception. I think the latter based on the reference to the original Viking image as true and the subsequent images as less than true.

Nobody likes having their religion challenged and for those people who believe that the Face on Mars is an artifical structure built by some alien race, these are clearly hard times. Recent imaging by NASA’s Mars Global Surveyor and Mars Odyssey missions, as well as ESA’s Mars Express (see this Astronomy Picture of the Day image), have clearly shown this feature to be nothing more than a naturally formed mesa in a region of Mars (Cydonia Mensae) in which mesas are common. Clearly, believers in the alien artifact religion are hard pressed.

That they are so hard pressed is further evident in how they choose to present relevant imagery. For example, take a look at the image below. The inset image is the original Mars Odyssey THEMIS image of the Face from the email. The main image is the original version from the Mars Odyssey web site found here. It’s clear that the version in the email has had its contrast enhanced and highlights boosted, obliterating detail present in the original image thus making the face look more artificial. Purveyors of this religion rely heavily on the ignorance of their audience.

Mars Odyssey Themis image of the Face on Mars
Mars Odyssey Themis image of the Face on Mars with inset image from email.

Why do I call this belief a religion? Because people still cling to this belief in spite of all evidence to the contrary. Which reminds me of a parallel situation. Over 100 years ago the astronomer Percival Lowell offered a complex and coherent explanation for the linear features that he observed telescopically on the surface of Mars. He claimed that they were actually irrigation canals built by the Martians to irrigate the equatorial regions of their dying planet. Despite mounting evidence that the lines he saw were nothing more than optical illusions, and no additional supporting evidence, Lowell clung to his belief – though for Lowell it was not a religion.

One good thing came about as a result of the email I received. In response to this email, I have just published on my Mars Art Gallery web site an article I had written last year discussing the Face on Mars and the visual perception law known as the Law of Prägnanz. If not for this email, this article would probably have never seen the light of day. The Law of Prägnanz and the Face on Mars is an article that explains why we perceive the face on Mars as a face. So my thanks to the sender of the email as that provided me the motivation to dust off the article and go public with it.

Ad Astra, Jim

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Phoenix Lander Safely on Mars

Sunday, May 25th, 2008
Phoenix First Picture of the Martian Surface
Phoenix Lander First Picture of the Martian Surface

Hurray. The Phoenix Lander has survived Entry, Descent, and Landing (EDL) to arrive safely on the surface of Mars. The radio signal indicating its success was received at NASA JPL at 4:53:44 p.m. Pacific Time. The signal was relayed from Phoenix to Earth via Mars Odyssey, now in orbit around Mars.

As I write this Phoenix has been on the surface of Mars for almost three and a half hours. Phoenix was launched August 4, 2007 and followed a Type II trajectory to Mars. It has landed in an arctic lowland plain in a vast region known as Vastitas Borealis. The longitude of the Phoenix landing site is 233 degrees East longitude. This lies to the east of the line of longitude on which the volcano Arsia Mons sits. Phoenix’s latitude is 68 degrees North. On Earth this would be in northern Greenland and very close to the Artic Circle.

Phoenix’s prime mission is to last 90 days. Believe it when you are told that this won’t be like the MER missions which have outlived their 90 day mission by years. Right now summer is just starting in the northern hemisphere of Mars and the Sun will be above the horizon all day. But as winter approaches, less and less sunlight will reach the solar arrays and the nights will get colder and colder. And there will come a day when the Sun doesn’t rise and before the winter is over Phoenix could well be buried under a foot or more of dry ice – the Martian version of snow. So this mission will effectively end sometime this November when Mars passes behind the Sun from our perspective and all communications with the red planet are cut off.

So Phoenix will have a short life, but let’s hope that it is a very productive one.

Ad Astra, Jim

P.S. My interview with WBBM radio (780 AM) about the Phoenix mission is to air sometime tomorrow (Monday).  Sometime after airing, the full 30 minute interview will be posted to their web site.

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Mars Phoenix Lander Interview

Wednesday, May 21st, 2008
Mars Phoenix Lander
Mars Phoenix Lander

Earlier today I made a trip to the local office of the Daily Herald in order to be interviewed for a WBBM-AM radio (780 on the dial) newscast. The interview was conducted by Steve Grzanich, reporter and co-anchor of the afternoon news at WBBM. For half an hour we talked about the Phoenix lander mission to Mars and its place in the exploration of Mars. We discussed past missions to Mars, current missions to Mars, how we benefit from the study of Mars, and what the prospects are for future human missions to the red planet.

In addition to talking about Mars, I was able to get in brief plugs for the Chicago Society for Space Studies, the National Space Society, and my upcoming presentation on space art at the International Space Development Conference in D.C.

I was also supposed to be interviewed by Julie, a reporter for the Daily Herald, but just as I arrived at the Herald’s office, she was called away on breaking news on the Drew Peterson escapade.

It was a fun interview and the time passed quickly. My long time interest in Mars is largely responsible for my work with the raw image data returned by various Mars missions, beginning with the Viking missions. I’ve been lecturing about the exploration of Mars since 1988 and it was my desire to provide unique images as a part of my presentations that got me started with processing raw image data instead of relying on images released by the NASA public affairs folks Prior to the Internet, the only way to obtain this mission data was by ordering CD’s from the National Space Science Data Center (NSSDC). Now the NASA PDS Imaging Node makes those data files easily accessible to anyone with an Internet connection.

I am told that the interview should air Thursday (tomorrow) afternoon and that the full interview will be available as a podcast in a few days on the WBBM web site. I’ll provide the details once I have them.

Ad Astra, Jim

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Does Photoshop Auto Levels Reveal Mars True Colors?

Tuesday, February 12th, 2008
Viking lander view of Martian surface
Figure 1. Viking 1 Lander color view of the martian surface.
Left: Mars as NASA shows it.
Right: Mars as Hoagland and company believe it to be using Photoshop Auto Levels.

The followers of Hoagland are at it again. They are still claiming that NASA is faking the colors of Mars – giving it a reddish sky when, according to them, the martian sky is really blue.

Quoting from their article posted 01/17/2008: “NASA has deliberately altered the colors of the images to make the Martian sky appear an absurd “Technicolor red,” when in fact all the evidence clearly shows that the true color of the Martian sky is (and must be) blue – just as it is here on Earth. In fact, when we used a simple color correction tool in Photoshop called the Auto Levels tool, Mars came out looking as Carl Sagan described it after the first Viking images in 1976 – it looked like Arizona.” Note that I am not including a link to the web site as the last thing I want to do is boost their standings in the search engines.

To illustrate what they are talking about, I went to the NASA JPL Photojournal web site and downloaded the same Viking image shown in conjunction with their story – see Figure 1 above. In Photoshop I duplicated the background layer and applied the Auto Levels command to that layer. I then cropped and downsized the image for display here. The left half of Figure 1 is Mars as shown on the NASA JPL web site. The right half has had Photoshop’s auto levels applied – resulting in a lovely blue sky. But is that really what the Martian sky looks like? Hoagland and his followers would have you believe that NASA, JPL (which is staffed and managed by the California Institute of Technology) and planetary scientists around the world are all part of a vast conspiracy that does not want us to know that the martian sky is blue. And since I am here to debunk Hoagland and company’s claims, I too must be part of that conspiracy. Cool! I’ve never been part of a conspiracy before – other than that age old parental conspiracy to convince their children that there really is a Santa Claus.

What about their claim that Auto Levels is a color correction tool? From the Photoshop Help description of the Auto Levels command: “The Auto Levels command automatically adjusts the black point and white point in an image. This clips a portion of the shadows and highlights in each channel and maps the lightest and darkest pixels in each color channel to pure white (level 255) and pure black (level 0). The intermediate pixel values are redistributed proportionately. As a result, using Auto Levels increases the contrast in an image because the pixel values are expanded (as opposed to being compressed, as in lower contrast images). Because Auto Levels adjusts each color channel individually, it may remove color or introduce color casts. Auto Levels gives good results in certain images with an average distribution of pixel values that need a simple increase in contrast.

So Auto Levels is not a color correction tool but a contrast enhancement tool that in certain situations may introduce a color cast. Note the qualifications that Auto Levels can give good results in some images and that the quality of those results is purely dependent on the distribution of pixel values. Pixel values is a reference to the luminance of a pixel – how dark or bright it is.

Back to Photoshop, lets review one more time what Auto Levels does. For each of the color channels – red, green, blue – Auto Levels takes the lightest pixel value in the channel and remaps it to white, takes the darkest pixel value and remaps it to black, and then stretches out everything in between. Now the consequence of this is that the brightest red, green, and blue pixels will now combine to form white because they have all been arbitrarily set to a value of 255.

Arizona sunset digital photograph
Figure 2. Digital photograph of an Arizona sunset

Let’s take a planet Earth example. Figure 2 is a photograph of an Arizona sunset that I took. On the left is the unmodified half of the photograph and on the right is the half as altered by the Auto Levels command. Why the large difference?

Photoshop Blue Channel Histogram
Figure 3. The Photoshop histograms for the blue channel of the Arizona sunset: before and after application of the Auto Levels command.

The histogram in figure 3 reveals what happened to the image. The histogram shows the distribution of luminance values for the blue channel before and after the application of Auto Levels. As you can see Auto Levels has significantly altered the distribution of luminance in the blue channel.

Now the question is which of these two images is a more accurate reflection of reality? Since I was there taking the photograph this is an easy question to answer. Auto Levels has both lightened the image and introduced a significant blue color cast and is not an accurate reflection of the sunset that I personally witnessed.

In closing, the claim that NASA, and the rest of the planetary science community, are lying about the true color of Mars and that the Photoshop Auto Levels command provides supporting evidence is baseless and without merit.

Ad Astra, Jim

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Imaging Mars for Naperville Astronomical Association

Monday, November 5th, 2007
Star Map of Mars at Opposition
Star Map: Mars at 2:23am CST 11/06/2007

Tomorrow night (Tuesday Nov. 6) I’ll be giving a presentation to the Naperville Astronomical Association. Titled Imaging Mars, the lecture will focus on the processing of raw PDS (Planetary Data System) IMG files in order to create attractive pictures of Mars. For the most part I’ll be using images from the Viking orbiters and Mars Global Surveyor. The work flow for transforming these IMG raw data files into finished images is rather straight forward. Things are a little trickier with the Mars Exploration Rover and Mars Odyssey images. As this is an introductory level presentation, I strive to keep it simple.

This is actually a good time to be talking about Mars as an opposition of Mars is fast approaching. On December 18, Mars will make it’s closest approach to Earth this opposition. At that time, Mars will appear 15.9″ arcseconds in diameter as seen from Earth. Not nearly as good as the opposition of 2003 when its diameter was 25.1″ arcseconds but the best we’ll be treated to until 2016. Thus this is an excellent opportunity to check out your local observatory or astronomy club for the opportunity to get a good look at the red planet.

As to my presentation: the Naperville Astronomical Association meeting begins at 7:00pm and is held in downstairs rooms A-B-C of the Naperville Municipal Center at Aurora Ave. and Eagle St. in downtown Naperville IL.

Ad Astra, Jim

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NASAView Limitations

Tuesday, October 2nd, 2007
NASAView JPEG vs GIF Comparison of a Mars Reconnaissance Orbiter HiRise image
NASAView JPEG vs GIF of a Mars Reconnaissance Orbiter HiRISE image

For those wanting to work with the raw data files returned by various NASA planetary missions the first order of business is to convert the data from its native PDS (Planetary Data System) IMG format into something usable by standard image processing software, like Adobe Photoshop. The NASA PDS Software Download site provides a variety of software packages for use in processing various NASA data products. For Windows users the only program available there for converting IMG files is NASAView. The most recent version of NASAView is 2.14 and was released in June 2007. Earlier versions of NASAView supported saving IMG files only as GIFs. Recent versions have included the option to save to JPEGs.

By design, GIF files are limited to 8 bits of color information per pixel. In the case of PDS IMG files, this means that each image is limited to a palette of 256 gray levels with 0 representing black and 255 representing white. Because the PDS IMG files from earlier missions contained only 8 bits of information per pixel, there was no data lost in the translation from IMG to GIF.

But what about when saving the IMG file as a JPEG. I do not know what the rationale was for adding the ability to save JPEGs. Perhaps so people could easily have an image that was more web friendly in terms of the file’s size. I strongly advise against ever saving an IMG file as a JPEG in NASAView. The reason is because of the JPEG compression. Unfortunately NASAView does not give the user any control over the level of compression. From what testing I have done, it appears that NASAView defaults to a quality setting of 75%. While this may be fine for dumping an image on the web, it fails when it comes to producing quality print images, especially if you want to enlarge the image.

To illustrate the impact of JPEG compression in NASAView take a look at the image at the top of this article. This is a 300% magnified view of a segment of a Mars Reconnaissance Orbiter HiRISE image. On the left is the JPEG version and on the right is the GIF version of the same area, only mirrored. The JPEG artifacts are obvious and take the form of square blocks. Of course there is a significant difference in file size. Whereas the GIF version is just about 7 megabytes, the JPEG version is just over 1 megabyte. Another differences between the JPEG and GIF versions are that the JPEG version is brighter than the GIF version.

In closing, my advice is that if you are using NASAView to convert IMG files to a standard graphic format file, never ever use the “Save JPEG” or “Save JPEG AS” options. If you need a JPEG version, then save your file as a GIF and use another pieces of software to do the conversion to JPEG so that you can control the amount of image compression used. Hopefully in the future a more robust version of NASAView will be released which offers Window’s users greater control on output file format and quality.
Ad Astra, Jim

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