
Dutch radio amateurs image far side of the Moon using Chinese satellite data - followben
https://www.camras.nl/en/blog/2018/precious-earth-and-lunar-far-side/
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z2
> The transceiver on board Longjiang-2 was designed to allow radio amateurs to
> downlink telemetry and relay messages through a satellite in lunar orbit, as
> well as command it to take and downlink images.

This is so cool and would have made such an impact on me as a kid if I got to
see it in action. I wish we could better demonstrate this sort of thing in
middle school or high school science classes, such as how easy it is to
download a weather satellite image live, via SDR.

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lalo2302
> designed by radio amateur and Nobel prize winning astrophysicist Joe Taylor

He doesn't sound like an amateur at all

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spiderfarmer
I am not a native speaker, but it is my understanding that amateur has 2
definitions: 1) unpaid, 2) incompetent or inept.

The Camras team is maintaining and operating the telescope on their own time.
The members have dayjobs like programmers and scientists, or are retired
professionals. So I'll go with the first definition.

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dtech
unpaid as in never having done something as a paid profession. A professional
software developer who retires and programs as a hobby is not suddenly an
amateur developer.

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Tor3
I don't think there's a definition like that anywhere. Only if you define
'amateur' as some who doesn't really know the trade. We should remember that
'amateur' actually means "lover of", i.e. that an amateur is simply someone
doing it because they love to (as opposed to "just" because they're paid to do
it). It doesn't say anything about the level.

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pvitz
This is amazing! I have a background in physics and electronics, but I have
never been involved in amateur radio. However, I would love to and would like
to ask if one could point me to resources for delving into it? When it comes
to math and e.g. electrodynamics and practical filters, I wouldn't need an
introduction. Thanks!

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Tor3
What I did was to find the local club, go there, learn about the next course &
exam, and focus solely on learning morse code (because I wanted the full
license). Because I had an electronics&radio background I didn't have to spend
any time on that part, I could focus all my time on the specific amateur radio
regulations (not difficult) and learning morse (although IIRC I still had to
take a written exam about radio transmission theory - not sure though, it's
been a _long_ time. I remember though that professional "telegraph" operators
from ships didn't have to take any exams at all, but I don't think that kind
of ship operators exist anymore. No morse code there, for sure..).

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moftz
CW coding hasn't been a requirement at any level for 12 years. Its good to
know but unless you want to do HF, it's irrelevant.

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Tor3
I only want to do HF.. but that's outside the point, I did write that this was
a long time ago, and at that time you did need CW to get the full license.

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testplzignore
What causes the pink hue in the original photos?

[http://lilacsat.hit.edu.cn/DSLWP-B/865fbeb5-116d-4f6a-bb86-0...](http://lilacsat.hit.edu.cn/DSLWP-B/865fbeb5-116d-4f6a-bb86-0a67a09b41ff.jpeg)

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tammojan
The camera used does not have all the filters for space. In particular it does
not have a UV cutter.

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arbitrage
Rock on, amateur operators!

HAMs did the same thing in the 60s, decoding Soviet communications coming from
the moon, which were the first closeup images of the surface at the time. They
released the images to wide fanfare, and did a lot to defuse the Soviets'
political agenda of holding this accomplishment above the western world.

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lixtra
Isn't it a copyright infringement to pick up some radio signal, reassemble it
to pictures and publish them?

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na85
Written with tongue only half in cheek:

Depends. In the US where media companies write copyright law and hand it to
legislators, yes. In China where there appears to be no Rule of Law, no.

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syntaxing
So interesting! How do you send "error-resistant digitally modulated
transmissions"? Is that the same thing as a duplex signal? Is there other
technology used nowadays?

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howard941
Could be coding (Turbo coding is where it's at, while hamming (no relation)
error correcting codes are purely digital and ubiquitous), could be simple
double transmissions separated in the time domain as in FEC SITOR/AMTOR. My
money's on Turbo coding.
[https://en.wikipedia.org/wiki/Turbo_code](https://en.wikipedia.org/wiki/Turbo_code)

~~~
syntaxing
Super interesting! Is this still the standard for this sort of communication
nowadays or are there successors?

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changoplatanero
How do pixels work in radio astronomy? Does the antenna only capture one pixel
every time the "shutter" is opened and then move to the next position?

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Someone
This is a normal camera, a normal radio that transmits it, and a large radio
telescope (once, over half a century ago, the largest in the world, but now
amateur operated;
[https://en.m.wikipedia.org/wiki/Dwingeloo_Radio_Observatory](https://en.m.wikipedia.org/wiki/Dwingeloo_Radio_Observatory))
used as an antenna to receive that broadcast.

I expect the data to be transferred one pixel at a time, but possibly, it’s
losslessly compressed.

It’s “Dutch radio amateurs image” because they controlled the camera.

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Uberphallus
They controlled the camera? I can't find any statement indicating so.

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tqkxzugoaupvwqr
> The transceiver on board Longjiang-2 was designed to allow radio amateurs to
> [...] command it to take and downlink images.

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harias
The RTL-SDR community at Reddit is a good place to look for resources if you
are looking to get into this:
[https://www.reddit.com/r/RTLSDR](https://www.reddit.com/r/RTLSDR)

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ninju
Dang...and I thought we would find all the aliens on the dark side of the
moon. Where did they all go?

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null_content
They are deep in Uranus.

