Am I going to need glasses for outside use?

[ShaOwned]

I just bought a 50mW greenie from O-Like

My understanding is that using it for outside use, starpointing etc, I won't need glasses.

But my super-smart PhD brother is telling me that it's still going to reflect off dust particles and stuff and I'll need glasses.

The reason I don't really want glasses is because I want to see the beam shoot and all, its kindof pointless to buy a laser, then wear goggles that make it not as bright in my opinion.

So can someone give me the lowdown, hopefully to convince my brother (and subsequently my mother) that I don't need goggles for these kinds of use?

Also, if I have misunderstood some other threads in this forum, do let me know if I SHOULD use goggles and perhaps address the concern I listed above.


Thanks in advance

 

[Eudaimonium]

Outside starpointing and messing around does not require glasses, on contrary actually.
If you put glasses on, you will not see the beam AT ALL, nor the dot for that matter.

Glasses are mandatory however, when you burn stuff and do indoor experiments (any kind of indoor use)

 

[Jaseth]

For any use in which you could:
Get hit directly by the beam
Get hit by a reflection (even quite weak reflections)
Or get very prolonged exposure to, or be very close to a diffuse reflection, proper safety goggles are mandatory for class 3B lasers (5mw to 500mw).

For outside pointing we must assume that there are no reflective surfaces present, that you will not be pointing the laser at yourself or letting someone else handle it, and that you will not shine it at anything close to you. Reflections off dust particles, fog and such do not pose an eye hazard, but they contribute nicely to beam visibility.Therefore, as Eudaimonium said, goggles are not necessary for star pointing, pointing at trees, mountains and such.

Please note that if anyone asks you to stop using your laser outdoors, even if you are not harassing anyone, it is best to just agree and stop. Theoretically, in many countries you would need a special permit to use a laser to point at the sky. Also be very careful not to point at all near helicopters or planes.

Seb

 

[ShaOwned]

Wonderful, thanks for your responses.

One more question: assume I am outside, and I point the laser at a wall straight in front of me for a few seconds.

Assuming I do not have goggles, what approximate distance would that wall need to be away from me to prevent vision damage?

Basically, could you expound upon the closeness you referred to in this statement:
"Or get very prolonged exposure to, or be very close to a diffuse reflection, proper safety goggles are mandatory for class 3B lasers (5mw to 500mw)."

 

[Jaseth]

"A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as from paper or other matte surfaces are not harmful. Continuous lasers in the wavelength range from 315 nm to far infrared are limited to 0.5 W."

Basically, according to many sources, it is not actually harmful to view diffuse reflections, such as you would get from pointing at a wall. While this is partly true, it does not take into account prolonged exposure such as that a person working with lasers all day will get. I also does not take into account if you have your face a few inches away from whatever you are pointing at.

Personally I stay a couple of feet away from any object I might point the laser at if I am not wearing goggles. I find that a good rule of thumb is not to look at the dot on a matte surface if it is uncomfortable with a green laser of that power. This means that, even if a 100mW blu-ray laser feels fine to look at from only about 1 foot away, you should not view it so close up since a 100mW green laser would be quite uncomfortable to look at this close.
Think of diffuse reflections a bit like the sun - you don't want to look at it if it's uncomfortable, and this is what saves you from eye damage.

If you point the laser at a wall about 5 feet or more away for a few seconds, the exposure is negligible and does not pose any eye hazard.

Seb