First TV Image of Mars: Interplanetary color by numbers (2016) | Hacker News Reader

First TV Image of Mars: Interplanetary color by numbers (2016)

directedplay.com

186 pointsgdubs36 comments

When my dad was working on Landsat images in the early 1970s they used to print out pages upon pages of numbers, color them in with markers, tape them up on a big wall, and then take a picture of it with a regular color camera. That is how they could print out color satellite images!

I did something in reverse. Our project was to maintain about 200 miles of a straight road in a diagonal direction on north-uo map, with another 90 miles road cutting it through making it a lop sided X.

I screenshotted Google Maps satellite view at certain height. It were about 30 sgots wide & 50 shots tall. Then cropped out the rectangle from shot with no distance scale, or search box. Then joined everything in Photoshop by hand. Then printed it as one gigantic page pdf. Then printed it on A3 pages as tiles with 1 inch overlap. Portrait wise 5 pages wide & 4 tall. Then trimmed every sheet on right & bottom except the last sheet on left & bottom. Then pasted them with glue. Cello tape on the back. Then everything goes on the wall. Then other people could use pushpins & stuff to mark the progress & program.

People forget that cut-and-paste used to be literally cut and paste.

Incredibly trivial example but, I did this for baseball score cards as a kid. My dad had internet at work but we didn't at home, so he printed some baseball score cards for me at work, and brought them home so I could pick one. But I wasn't happy with any particular one of them, so I went to our local copy shop and sat there for a couple hours happily cutting and gluing together the elements from all of them that I wanted to create the ultimate baseball score card.

We did this so much. Nothing quite as impressive as your monster map!

Need to know the area of that road? Cut it out and weight it. Divide it by the paper weight (e.g. 80gsm or more accurately weight a few pages and measure areas to get an average).

InkAtlas does this for OSM tiles. I've used it a bit, but never needed a map large enough to use the paid option.

Url changed from https://kottke.org/22/12/our-first-closeup-image-of-mars-was..., which points to this.

For those in or are visiting the LA area, this image is on display on the free-to-the-public JPL tour. Highly recommend!

https://jpl.nasa.gov/events/tours/

Makes me think of the early satellite photography that was captured using analogue cameras, which were mounted on satellites orbiting the Earth. When the satellite finished its mission, the camera would be released and fall back to Earth, attached to a parachute. A team of technicians would then locate the camera, retrieve it, and bring it back to a laboratory where the film would be developed by hand in a dark room. This process was labor-intensive and required a great deal of expertise in order to produce high-quality images.

This technique is generally known as indexed color.

https://en.wikipedia.org/wiki/Indexed_color

It’s simpler than that; the pixels were just light intensity values (per the article, they had originally intended to get various shades of grey chalk). The scientists just wound up applying their own “palette” to the intensity values.

It does not make a lot of sense to me that it would take hours for a computer to generate an image, but the computer could promptly print out the data in human decimal representation.

You have to remember that back in those days, for a computer to generate an image did not mean for it to render an image on a screen like we do today. It meant generating an image to be printed on paper using the same kind of technology that was used for printing magazines and newspapers. That was a time-consuming physical process, not so much a time-consuming computational process (though it was probably that too back in 1965).

The issue was not processing time but bitrate. Mariner 4 sent data back at something like 8 bits per second, and the science team printed it and colored it as it came in.

I agree. I used to print images by using characters with more ink for the darker blots, down to a single dot (period) or even a blank space for the lightest. Looked pretty good.

> Though he used a brown/red color scheme, the thought that Mars was red did not enter his mind. [...] It is uncanny how close his color scheme is to the actual colors of Mars. It’s as if they came right out of current images of the planet.

I'm sceptical. If you look at Mars from Earth, you can see it's red even without a telescope.

The article isn’t saying that he didn’t know it was red, but rather that he wasn’t actively thinking about trying to match the color. Obviously there’s a question of conscious vs subconscious thought, but the claim is at least that he chose red/brown because it would represent grayscale well.

Yeah, I'm pretty sure that the science guy in the 70's knew which color Mars was.

Coming from a blue planet there might be some color bias. We should really observe from the moon which seems to have a neutral color.

This is where I start to give credit to a lot of Mars conspiracies. I know that the cameras on the Viking probes were tested and calibrated on Earth to give accurate colors, the probes themselves had color calibration chips on their hulls that the cameras could use for testing and recalibration, yet for some reason the sky and ground on mars was always shown as red hued (like in the 80s Total Recall movie), or maybe the sky was a little yellowish - until it wasn’t! Suddenly one day Mars had a blue sky and most of the rocks are grey, and only the soil is red. Not any real explanation I’ve ever heard, just oh by the way the sky on Mars is blue, in other news…

The color of the Martian sky depends heavily on how much dust is in the air, but it's generally orange-ish, while a dust-free sky would probably be black! People have scienced the hell out of this. For example see: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...

The question of what it would look like to human observers is another matter. A lot of photos from Mars are color adjusted to try to capture what we'd see if we went in person.

Is there anywhere to get the actual image data, in either text or bitmap form? The photo of the print version isn't terrible but it's not particularly good either.

That's kind of a weird way to put it... as if the image came from the TV?

"TV" in this case is short for "televised". That is, it came via a radio signal, rather than being physical film brought back from Mars.

But of course, the bandwidth is far too low to be an NTSC signal and it was digital rather than analog, so actual existing TV equipment couldn't have helped. For the moon landings, it was an actual NTSC television signal generated on the surface of the moon, amplified by ground receivers, passed through real-time scan conversion to bring the FPS to 30, and sent to broadcasters.

>> “The thought that Mars was red did not enter his mind”.

Not sure about that. It was assumed to be red since 400BC [1]. One needs only to look at it without the aid of a telescope to jump to the conclusion that it might be red.

[1] https://mars.nasa.gov/allaboutmars/mystique/history/early/

To me that sentence doesn’t mean “the scientist didn’t know Mars was probably red”, but rather means “the scientist didn’t pick red to try and color match Mars, but for a different reason”

It seems unlikely to me. I get that he wanted to do greyscale since that is all of the information that the sensors provided. However, picking a non-red colour set, knowing that the planet is red is absurd.

Eh, maybe? We can’t reach into his mind.

I really don’t see a motivation for them to lie in this particular context (literally no one would be mad if they said “we choose red markers because we thought Mars was probably red”). And I can understand being in a frantic state of mind to decode the first image of Mars as fast as possible, and the conscious consideration of the color set just not coming up. That sounds perfectly plausible to me.

If that story is true, I’d also be pretty inclined to believe they were subconsciously influenced to pick a red color, even while hurrying. So, I don’t think it’s a total coincidence, but nothing about the story sounds particularly far fetched to me.