TorchBoy
Flashlight Enthusiast
Re: Wicked Lasers 445nm 1W(!) portable deathray
I found myself wondering how powerful the lasers are that are used for lunar ranging. Answer: 2.3 W. They are very careful with the laser: http://www.physics.ucsd.edu/~tmurphy/apollo/basics.html
Hm...
I found myself wondering how powerful the lasers are that are used for lunar ranging. Answer: 2.3 W. They are very careful with the laser: http://www.physics.ucsd.edu/~tmurphy/apollo/basics.html
So 2.5 W spread over the area of a 3.5 m telescope is "almost eye-safe".Is it safe?
It's all fun and games until someone shoots an eye out! Working with a powerful laser demands some attention to safety. We follow strict safety guidelines when working around the laser, wearing protective glasses that only admit one ten-millionth of any laser light hitting them to pass through. But once we have expanded the beam to fill the 3.5 meter telescope aperture, it is far less dangerous—almost eye-safe, in fact (far too weak to cause damage to anything but eyes or sensitive detectors). Nonetheless, we are diligent about not hitting aircraft, which, more than creating an eye-hazard would potentially startle pilots. Some have reacted in horror when we tell them that we are shooting a laser at the moon. "Why would you want to destroy the moon?" Rest assured that 2.3 watts of laser power spread over a 2 kilometer patch on the moon is nothing compared to the sun's 1380 watts per square meter. Not even enough to tickle.
Hm...
A rough figure for sunlight at Earth's surface is 1 kW/m^2, so the atmosphere attenuates light by a factor of ~0.72. You could include that in your calculations, AAS.Let's assume the atmosphere has no effect on the beam.