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Histograms in photo displays, when did it start?
dvandorn
post Jun 12 2007, 04:20 AM
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I know that by the time the Voyager Jupiter encounters began, images coming in "hot off the wire," so to speak, were displayed (on TV, anyway) with histograms alongside the images.

Was this when the practice of showing histograms along with the images began? If not, when did the practice start? I don't recall seeing them on Mariner 6/7 images, or on Mariner 9 images. Were there histograms on the initial public release images from Mariner 10, or either Pioneer 10 or 11? (I have my doubts about the Pioneers, as they had a scanning photomultiplier tube in lieu of a real camera.)

And note that you don't see it much anymore -- when did the practice stop? Or was it really mostly done just during the Voyager encounters?

Anyone remember?

-the other Doug


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ugordan
post Jun 12 2007, 08:42 AM
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I was too young to actively follow the Voyager mission back then (without the internet it would have been impossible, anyway), but I think I know what you're talking about. I have a neat GIF image somewhere (wish I could dig it up now) showing Neptune inbound, from some 600 000 km, in real time with Voyager 2 telemetry and all sorts of cool (to a kid anyway) numbers and abbreviations on screen. It was obviously a TV screen capture. I've seen the same format in documentaries about the mission dating back to the Saturn encounters. And yes, there was a histogram displayed. The raw images were automatically histogram stretched IIRC for preview displays so this was probably added as a coolness factor.

As far as other missions are concerned, were there really such live TV monitor images shown before the Voyagers? In Cassini's case, back in the day of SOI and those ring closeups, as well as Titan flyby 2 days later there were live broadcasts with imagery displayed on large screens with a bit of information. There may have been a histogram alongside, but as I recall no auto-stretching was done (there were ring images that were very bland for example). The onscreen imagery was certainly less telemetry-packed than was the case with the Voyagers.


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dvandorn
post Jun 12 2007, 06:09 PM
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Oh, yes, there were live TV displays of incoming images prior to the Voyagers. The first that I can recall in detail was from Ranger IX. As it plunged into the Moon, the output from one of the cameras was fed directly to a TV feed, real time. For the first time in history, the title "Live from the Moon" was displayed on my TV screen.

I also recall that the first image from Surveyor 1 was broadcast live as it was received at JPL. It was a low-res (200-line) image of the footpad and the soil disturbed by the footpad. It was the first image of a footpad settled down on the surface of another Solar System body. I remember it well.

The Mariner 6 and 7 far-encounter sequences were shown real-time, at least on CBS. (Walter Cronkite, after just finishing up his network's coverage of Apollo 11 less than a month before, was not going to let live TV pictures of Mars go without live coverage.) I don't recall the close-encounter sequences being covered live, but for all of me they might have been.

The first Viking 1 lander image was also displayed real-time, as it built up line by line. So was the second image. And, of course, the images from Pioneers 10 and 11 from Jupiter and Saturn were presented real-time. They were very poor, since they had yet be corrected for spacecraft motion during the image build-up process, but even so, they were shown real-time.

I just don't recall any of them, except for the Voyager images, having the histograms displayed on the live feeds.

-the other Doug


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ugordan
post Jun 12 2007, 06:16 PM
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Ahh, yes, this brings back memories:
Attached Image

Actually looks like a shot off a TV (news?) feed, judging by the ghost images. Seeing as this was probably primarily a closed-circuit TV thing at JPL and not meant for public broadcasts, it's logical they added all this other info the general public couldn't comprehend. wink.gif


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Ian R
post Jun 12 2007, 08:47 PM
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The following screenshots are taken from a UK TV documentary on the Neptune encounter. Candy Hansen cuts up a printout of a Voyager 2 image of Triton in an attempt to reconstruct an ancient crater that was subsequently destroyed by tectonic activity:

Attached Image


Attached Image


Attached Image


Ian.


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Ian R
post Jun 12 2007, 09:01 PM
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And a couple of shots of the Voyager 1 OPNAV image in which Linda Morabito discovered two active volcanoes:

Attached Image

Attached Image

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The last one is very 1970s! biggrin.gif


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