General > General Technical Chat
"Backyard Scientist" - idiocy never fails to astound me
jogri:
--- Quote from: TimFox on August 02, 2020, 01:21:40 pm ---Physicians used to use "fluoroscopes", where a fluorescent screen was placed between the observer and the patient, and x rays were sent through the patient to the screen. It was necessary to dark-adapt ones eyes before the examination. I shudder to think of the dose to all concerned with these inefficient screens. The modern equivalent uses image-intensifying equipment and enhanced screens (with metal sheets that convert the x-ray photons to electrons that give more light from the screen).
If you look at the spectrum of photons from an x-ray tube, you see the characteristic (e.g., K-alpha) lines sticking up from a broad spectrum from Bremsstrahlung that has a definite end-point corresponding to the tube voltage. The mean energy is substantially lower than the voltage, and the lower part of the spectrum is attenuated by "filtration". For medical uses, typically an aluminum filter plate is inserted in the tube window to reduce the low-energy photons, since they are absorbed quickly and don't contribute any useful information to the image, but damage the patient's skin.
--- End quote ---
One thing to add about those nasty things: They were not just used for a quick examination, but during entire operations in war times to find bullets/shrapnel inside of patients... You had to turn the patient regularly if you didn't want him to get a xray "sunburn".
@Lord: With the right optic that's not a problem at all (+if you have the right laser), all Apollo missions left corner reflectors on the moon to determine the Moon-earth distance (you get a 6.5 km wide beam at the moon...). This guy probably had a 915/980nm IR laser and since nothing in the air absorbs at those wavelengths, he could have reached the ISS. But i'd take the guess that his small DIY Cassegrain reflector wasn't designed for this use, so the beam probably expanded way too much to be visible against background.
coppercone2:
--- Quote from: Lord of nothing on August 02, 2020, 01:43:58 pm --- ::) Stupid Question could the Laser Guy with his "Death Ray" reach the ISS? :o
I would say its not a good idea to blind some Astronauts.
On the other Hand get some Keyhole Sat out of Business are not a bad idea. :-DD
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the ISS moves too quick and the beam will be too diffuse at that point to do anything but potentially mess with sensors (possibly something used for weather / spectroscopic studies)
Not to mention the air force (space force) will probably send something to investigate if its persistent. It's probably considered a threat to early warning satellites for missile detection.
btw what do you call the space force version of special forces for dealing with ground based stuff that effects space? red shirts?
KL27x:
China: sends $1500 laser in pink foam and cardboard.
US component distributor: ships an IC socket in foil bag.
edy:
I also enjoy styropyro's videos... he is hilarious in a sarcastic sort of way. In this video he tests a laser tattoo removal system from China that ends up destroying his cameras (and hopefully not his eyes):
He is very funny and does some crazy builds too all while still managing to be quite educational for a YouTuber.
bsfeechannel:
This guy does it the safe way.
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