Laser usage safety

[Violet]

Hello.

I recently bought a 75mW 405nm laser. I don't plan on using it inside without glasses on but I was wondering how safe it was to use outside pointing at the sky/trees without using glasses. I've only used it for a few seconds so far outside without the glasses and I love the way it looks, I would hate to always have to hide its true colors so to speak.

 

[NKO29]

Well, i'm a not complete idiot BUT I have used my 1W+ 445nm indoors without glasses. <-- this is a fu$%ing bad idea and do not quote me on this at all! but when done in a "safe manner" your eyes will not be harmed if nothing goes wrong.
I always use this laser for pointing at stars without goggles and this is commonly seen as a "safe practice" because the humidity in the air isn't enough to reflect many photons back at you. But as for pointing at trees, if there happens to be a reflective surface in or around it there is a minute chance that it will reflect back at you.
edit: Oh btw 405nm is at the very low end of the visible spectrum... Even though it may look a bit dim, you are probably underestimating the power

 

[Leodahsan]

laser "usage" is a vague term.
If "usage" applies to shining a laser around your house - that can have reflective surfaces, mirrors, other people, pets, its a disaster waiting for happening
Same for shining a laser on the sky - where we have airplanes.

If "usage" applies to a well planned experiment, inside a closed room, with no one else inside, with a adequate beam stop (or at least a dark, non-reflective target), with a low power laser, then it should be ok.

Experience and care is needed for proper laser appreciation

Anyways, its just wrong to say "never turn the laser on without goggles". It just depends on laser power, environment, etc. Just don't do anything stupid.