[LMB] OT: Arecibo
baur at chello.at
Sun Nov 22 20:15:02 GMT 2020
Am 22.11.2020 um 21:00 schrieb Luke Bretscher:
> On Sun, Nov 22, 2020, 12:41 PM Howard Brazee <howard at brazee.net> wrote:
>>> On Nov 22, 2020, at 10:54 AM, Pouncer via Lois-Bujold <
>> lois-bujold at lists.herald.co.uk> wrote:
>>>> One of the functions Arecibo excels in is tracking asteroids
>>>> well enough to warn us of possible dangers to us.
>>> Oh. I had been under the impression that OPTICAL telescopes
>>> were somehow better at picking out dead ice and rocks in
>>> local environments, while RADIO-telescopes like Arecibo were
>>> more stellar ... so to speak.
>> Arecibo actually uses radar.
> Radar as opposed to radio? I'm not sure what distinction you're drawing.
radio is passive - it listens only ..
radar is active - it fires out a pulse and listens to the echo .. i.e
for asteroid work you not only need a a very sensitiove recive (=large
antenna) you also need a very poweful transmitter
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