Beam brightness

[carlos3621]

The longitudinal meridian, along with sextants for calculating latitude and clocks that could keep time at sea enabled the British fleet to navigate and map the world.

It is the datum for every map of the Earth and seperates the eastern and western hemispheres.

Yeah BEN! , what Doc said

[White-Light]

Sorry to hear about your tinnitus, my Dad suffered badly from the condition

Bit too late for you Graham although it may still help - I always use Alpine Clubbing plugs (usually with the low (white filters) - they ship with 3 sets low, medium and high attenuation) whenever I go anywhere these days. They're designed to apss all frequencies just at a lower level so you don't get the muffled effect of ordinary plugs. Wouldn't say they are perfect on all frequencies but they're damn good! http://www.juno.co.uk/ppps/products/274473-01.htm

I used to club without but started getting intermittent tinnitus when I'd been no where near loud music for months almost on a daily basis. Since I've been protecting my hearing I hardly ever get any trouble at all. Can't remember the last time I had a tone in my ear and I never have any after an event. Well worth the £15 I paid for them!

[Laser Ben]

Obviously this post wasn't needed...

[instinct]

Because Rayleigh and Mie scattering both tend to deflect the beam path only very slightly. So if it's already headed towards you, the beam doesn't need to be scattered very far off it's original path for some of the light to enter your eye. But if the beam is going away from you, the light needs to make a 180 degree turn to get to your eye, and that's not the way scattering works. (Some does still reach your eye, of course, but it requires *many* successive scattering events in order to do so, thus the intensity is lower.)

Note that if you were using REFLECTIVE particles instead of a fog or haze, then the beam would look brighter when it's headed away from you, since reflection *does* cause a large change in the beam path.

Adam

What reflective particles could you use? Glitter?

[buffo]

What reflective particles could you use? Glitter?

Or dust. Dirty chalkboard erasers work *really* well. Just don't let it get on your optics...

Adam