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Voyager launched in the 70s. At that time, modern CCD or CMOS image sensor may not have been available.

So how does Voyager take pictures in space, digitize the image and send it back to us?

The details of Voyager's cameras don't seem to be public at NASA.

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    $\begingroup$ Simply Google 'Voyager 1 cameras' and you get e.g. this: physics.stackexchange.com/questions/25005/… $\endgroup$ – Jan Doggen Oct 13 '17 at 15:44
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    $\begingroup$ You're looking at the wrong site. NSSDC focuses on science results, not instrument descriptions. The info you're looking for is here: voyager.jpl.nasa.gov/mission/spacecraft/instruments/iss $\endgroup$ – Hobbes Oct 13 '17 at 16:02
  • $\begingroup$ Video cameras existed long before modern CCD or CMOS image sensors. Analog to digital converters existed also in the 70s. $\endgroup$ – Uwe Oct 13 '17 at 20:06
  • $\begingroup$ There is very few information about the image sensor in voyager.jpl.nasa.gov/mission/spacecraft/instruments/iss , just the word vidicon, but not more. $\endgroup$ – Uwe Oct 14 '17 at 14:10
  • $\begingroup$ @uwe vidicon is another name for a video camera tube. As you noted, they don't give many more details, such as its size or resolution, which would have been nice to know. $\endgroup$ – FKEinternet Oct 15 '17 at 5:19
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Voyager's camera used a vidicon tube, which is sort of a vacuum tube precursor to a CCD.

I don't 100% understand the principle, but the basic idea is that the image is captured on a photoconductive surface, thus converting it to a pattern of electrical charge; an electron beam is raster-scanned across the photoconductor producing a varying voltage out of the system, which can be amplified and converted to a digital data stream. It's something like a television operating in reverse.

To get color, you take multiple pictures with different filters in front of the camera for each one.

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    $\begingroup$ A CCD is an analog image sensor, see en.wikipedia.org/wiki/Charge-coupled_device just as a vidicon tube. A CCD is a solid state integrated circuit, a vidicon is a vacuum electronic tube. The analog output signal of both sensors may be digitized. $\endgroup$ – Uwe Oct 13 '17 at 21:56
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    $\begingroup$ Helpful discussion by Emily Lakdawalla: youtu.be/RpG-SRx9HSg and here is the video of Voyager 1 images that she mentions; youtu.be/rHwkdcppsuo Helpful discussion and graphics: allaboutcircuits.com/news/… $\endgroup$ – uhoh Oct 14 '17 at 7:43
  • $\begingroup$ @uhoh : A very good description of the Voyager imaging system in your link from allaboutcircuits with a nice graphic of a vidicon tube. The resoultion of 800 * 800 pixel looks very small for our megapixel viewpoint, but in the 70s, 640 kP was a good compromise for a very reliable solution that should work in space for many years. $\endgroup$ – Uwe Oct 14 '17 at 12:35
  • $\begingroup$ The image in the link from allaboutcircuits does not show the correct orientation of the horizontal and vertical defelection coils. To deflect the electron beam, a perpendicular magnetic field is necessary, not a parallel field to the electron beam. See en.wikipedia.org/wiki/Deflection_yoke for the orientation of deflection coils. $\endgroup$ – Uwe Oct 14 '17 at 14:06

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