[Pseudoscience-is-malarkey (OP)]

When images were sent to earth from spacecraft before the 80s, of planets, moons, etc, how were they sent, transmitted, and received?

[Bored chemist]

Digitally.
https://www.open.ac.uk/library/digital-archive/program/video:FOUT123J

https://en.wikipedia.org/wiki/Fax#History

[evan_au]

Chemically: The astronauts on the Moon took Hasselblad cameras* which exposed large-format film (colour or black-and white).They were returned to Earth for developing the images.
https://www.hq.nasa.gov/alsj/a11/a11-hass.html
*Other brands were available to them...

Some of the early spy satellites exposed chemical film from Low-Earth Orbit, and dropped the canister of film into the atmosphere, where it was slowed by a parachute, and snagged mid-air by a pre-positioned airplane, and delivered it for film development on the ground.

[alancalverd]

The "digital age" began in 1837, long before any form of powered flight, let alone space travel.

[Petrochemicals]

https://en.m.wikipedia.org/wiki/Mechanical_television

[Pseudoscience-is-malarkey (OP)]

So let's say this then... You're a journalist and the year is 1938. You're in Germany covering Hitler's annexation of Austria or the Sudetenland and you or one of your men snap some photos of this hugely important international event for your newspaper in the UK or the US or whatever. What technological process is at play here when you're sending them instantly? How did technology receive signals and turn them into a photograph?

[alancalverd]

The original "fax" machine was a Muirhead Optical Scanner that worked on the same principle: the intensity of light reflected from a point source scanning the original, was converted into an analog frequency that was transmitted through the telephone system and reconverted at the receiver into light intensity (for a photographic reproduction) or dot size (for making a newspaper printing plate). Very slow but remarkably good quality.

I think the encoding standard was worldwide and various manufacturers (probably Telefunken in Germany) made compatible devices - just like fax.

[evan_au]

The "digital age" began in 1837

I assume that you are talking about Morse Code, a form of digital ON/OFF keying.

In the days before television (and before voice could be transmitted over undersea cables), the Australia vs England test matches played in England were broadcast "live" over radio/wireless in Australia.
- People in Australia had watched many cricket matches, so they had no problems forming an image of the action in their minds, based on a wireless broadcast.
- But the digital transmission from England to Australia was interesting:
- Someone watching the game in England would write a very compact description of the action.
- A chain of morse code operators would transmit this short message to Australia
- A radio announcer in Australia would narrate the action as if he were watching the game live
- The sound of the ball hitting the bat was emulated by tapping a pencil on the desk...

[alancalverd]

I assume that you are talking about Morse Code, a form of digital ON/OFF keying.

No, actually - I was thinking of Babbage's Difference Engine, but the coincidence is extraordinary.

Part of me wishes I'd been born a hundred years earlier, when science and engineering were making the greatest leaps in human understanding and welfare. Even in the 1960s you could use a few precious kilobytes of memory to fly to the moon - really exciting stuff, and now people devote zillions of megabytes to pointless crap like Twitter, selfies and computer games.

Cricket still sounds good on radio.  BBC Test Match Special broadcasts are the height of intelligent drama and comedy. Tennis is actually less boring on radio than television - I recall being gripped by the 1975 Arthur Ashe / Jimmy Connors Wimbledon final whilst driving round London, having just met the love of my life. Radio soccer gave us an immortal cliche: in the 1930s the BBC published a diagram of the soccer field divided into numbered squares, and a safe pass to the goalkeeper was described as "back to square one".

[Pseudoscience-is-malarkey (OP)]

people devote zillions of megabytes to pointless crap like Twitter, selfies and computer games.

That's subjective.

[evan_au]

Back around the year 2000, I bought a 2 Megapixel digital camera; the images were around 200kBytes each.
- For many people, the internet ran at around 30kbps over a diallup modem.
- If you wanted to transfer some pictures to someone across the room, it was often faster to copy them onto a "floppy disk" (with a storage capacity of around 1 MByte), and walk across the room with it.
- Presumably, the same situation would occur today with a 64GByte flash drive - it would be faster to walk than to transfer over broadband.

This pedestrian method of image transfer was dubbed "sneakernet".

[Pseudoscience-is-malarkey (OP)]

Back around the year 2000, I bought a 2 Megapixel digital camera

What went through your mind when you decided to do that? Did you just wake up one day and decided "I'm going to buy a 2 megapixel digital camera"?

[alancalverd]

Probably the same as went through my mind around the same time. It was a pretty good investment.

[evan_au]

What went through your mind when you decided to (buy a 2 Megapixel digital camera)?

Correction: I just pulled up one of my old images, and it is 780k pixels (1024x768), but that may not have been maximum resolution(?).

The reason for getting a digital camera was that I was posted to Belgium for work (with my family), and we wanted to capture photos of what we saw.
- The memory sticks of the day could not hold many photos!

The image below is a visit to the ESA Space Shuttle training facility, in Belgium, December 1999.

Space_school.jpg (251.61 kB . 1024x768 - viewed 1922 times)

[vhfpmr]

The "digital age" began in 1837, long before any form of powered flight, let alone space travel.

The ancient Chinese were using smoke signals ~1000BC

The original "fax" machine was a Muirhead Optical Scanner that worked on the same principle: the intensity of light reflected from a point source scanning the original, was converted into an analog frequency that was transmitted through the telephone system and reconverted at the receiver into light intensity (for a photographic reproduction) or dot size (for making a newspaper printing plate). Very slow but remarkably good quality.

I saw slow scan TV at the local amateur radio club in the early 70s, but that's analog, not digital.

[Petrochemicals]

Back around the year 2000, I bought a 2 Megapixel digital camera

What went through your mind when you decided to do that? Did you just wake up one day and decided "I'm going to buy a 2 megapixel digital camera"?

Probably the same motivation that led half the world to wake up one day in the 1960s and say, I'm going to get rid of my slr with zoom lens and replace it with a 38mm lens  point and shoot fixed aperture camera, or god forbid a 110 cartridge or Polaroid.

[alancalverd]

That would have been silly. 2 Mpx was a sensible, affordable camera 23 years ago and my Canon Sureshot, unlike my 35 mm SLR, could record  video. The zoom was better too.

[Petrochemicals]

That would have been silly. 2 Mpx was a sensible, affordable camera 23 years ago and my Canon Sureshot, unlike my 35 mm SLR, could record  video. The zoom was better too.

Ahh video, hours and hours of people recording their holidays on camcorders, to go home and enforce 10 hours of mundane poor quality video shot in a shaky badly framed fashion on their relatives.

[evan_au]

Canon Sureshot...The zoom was better too.

My digital camera was a compact fixed-focal length model.
- Great for emailing photos home and creating a digital photobook.
- Without waiting to fill 35 pictures on a roll, then wait to get it developed
- This also avoided a few language problems when traveling around Europe, and you struggle to read the local language on the film packaging...
- I recorded the pictures on writeable CD-ROM; but my current computer doesn't have a CD reader, so I transferred them to an external hard disk.

[alancalverd]

Ahh video, hours and hours of people recording their holidays on camcorders,

Before Facebook, you had to photograph your lunch, rush to the chemist, get the film developed, make 25 postcard prints,then go to the post office and send them to your friends, by which time the meal was cold.
But whilst Evan can't see his recent photos on  his new computer, I still have black and white prints of equipment I built nearly 60 years ago, and if you want a good picture of an extinct bison there are plenty of 40,000 year old cave paintings that show you how to hunt them with spears.