Ban of Handheld Lasers within 10k of airports

[Rockie]

Try hitting a 6x6 post with one of those laser distance measuring things from 40ft, it is really hard to do. So how would the average person expect to hit a fast moving object at 6000 ft?

Anybody that has a laser knows the beam diffuses over distance.

I refuse to believe those 400 people in toronto tried to bring down the plane or harm anyone on board. Maybe one lunatic might be trying to do so, not everyone.

I agree, that's why I'm going with the "stupid" explanation. It's the kind of stupid only a smack to the head will fix, listening to teacher won't do it. This has received considerable news coverage over the years along with this announcement of new penalties. It'll be interesting to see if "education" has the impact you think it will...it hasn't yet.

[digits_]

Anybody that has a laser knows the beam diffuses over distance.

False

[Rockie]

The coherency of the beam is the very reason people buy lasers, so if they shine it on anything how could they not notice that it diffuses over distance? It's probably the first thing they check. Confusing.

[digits_]

The coherency of the beam is the very reason people buy lasers, so if they shine it on anything how could they not notice that it diffuses over distance? It's probably the first thing they check. Confusing.

Coherence is different from divergence. A property from lasers is that they are non-divergent for a long time. That is why they buy them as well. They are also coherent and mono chromatic.

Laser applications use the non-divergent properties. Expecting people who buy a "non-divergent" laser for fun to know that it does diverge can only be achieved by education.

How would you expect them to see a laser diverges after, for example 2000 ft? They wouldn't even see the dot unless they have some fancy binocular gear.

[Rockie]

Any laser I've seen diverges noticably within a large room. What kind of laser can you buy that doesn't diverge until 2000 feet, and why would Joe Laser guy buy one expecting it to be a death dot and then use it on an airplane?

You're just raising more questions with every post.

I thought I was pretty clear that people buy lasers because they're coherent...as in they do not diverge. That suggests I know the difference between the two but I apologize if it was confusing.

[B208]

Why do you think they aim it at an aircraft?

Because they haven't been educated as to how dangerous it is.

[Rockie]

Why do you think they aim it at an aircraft?

Because they haven't been educated as to how dangerous it is.

If that's the case wouldn't there be similar incidents of pets, kids and themselves being blinded? What a great party trick shining a laser in little Susie's eyes at her birthday party eh?

You know, since they don't know it's dangerous and all...

Yes you say, but it diffuses over distance right and they know that which is why they shine it at airplanes but not their kids eyes. But digits_ is saying they don't know it diffuses. So they don't know it diffuses, and they don't know it's dangerous. ER's must be full of people with laser blindness.

Questions...questions...

[B208]

Why do you think they aim it at an aircraft?

Because they haven't been educated as to how dangerous it is.

If that's the case wouldn't there be similar incidents of pets, kids and themselves being blinded? What a great party trick shining a laser in little Susie's eyes at her birthday party eh?

You know, since they don't know it's dangerous and all...

I'll start by saying it has been a while since I worked with lasers, (it was during my senior research project back in university.....so quite some time ago), but I recall that there were certain wavelengths, (near the UV end of the spectrum), that caused
immediate and permanent eye damage. Lower energy wavelengths (near the red end of the spectrum) don't cause eye damage. All of the laser pointers on the market today are low power and red. That, I suspect, is why we don't have ERs full of blind Susies

[Rockie]

Honest question, the one that hit me was blue and very intense even at 6500 ft. What kind of laser would that be and could it be purchased commercially?

[B208]

It was not a standard laser pointer. Could have been a burning laser scavaged out of an old laser engraver. Could have been a home built laser (plenty of sites tell you how to build your own). The parts are all available either on line or from scavenging old electronics. A determined 15 year old of average intelligence could put one together.
Also, green/blue is the higher end of the spectrum; that one could have burned out parts of your retina. I'm glad it wasn't that close.

[Rockie]

Also, green/blue is the higher end of the spectrum; that one could have burned out parts of your retina. I'm glad it wasn't that close.

Me too, it was fearsome enough from 6500.

[digits_]

Okay, lots of info to go through.

Let's start with the little tangent about terminology:

I thought I was pretty clear that people buy lasers because they're coherent...as in they do not diverge. That suggests I know the difference between the two but I apologize if it was confusing.

Respectfully, the bold quote does indicate you do not know they are different. They are not the same. They are different properties of a laser.
Coherent means that the wavelengths of the light are in phase. This is important for data transmission applications and lots of experiments. For our "blind the pilot" task, this is irrelevant (unless you are trying to beam updated SOPs through his retinas )
Divergence/divergent measures or refers to the widening of the beam. A laser has a very small non-zero divergence.


Granted, in our discussion it doesn't really matter which word you used, you and me are both referring to the diverging beam. I do admit I find it a bit funny that the wrong terminology is being used as a rebuttal to my suggestion to educate people more about lasers.

Any laser I've seen diverges noticably within a large room. What kind of laser can you buy that doesn't diverge until 2000 feet, and why would Joe Laser guy buy one expecting it to be a death dot and then use it on an airplane?

Let's consider 2 lasers:

1) Laser A: a theoretically perfect laser. Does not diverge. All its power stays focused in the same narrow beam/dot, independent of distance
2) Laser B: a powerfull real laser. This laser does diverge and its power/beam spreads out like a cone.

Joe Laser wants to buy a laser to play around with. He doesn't know too much about it, but he is interested in it, and wants to shine on some objects. He buys laser B, but thinks he is buying laser A. Why? Because of movies, books, sci fi, flyers and promo material of the manufacturer. It's an expensive laser, so it must be close to perfect.

Joe is having fun shining at objects and he notices planes are flying over his house very often. He managed to shine on his neighbour's car, would he be able to hit the plane? He might even know he is not supposed to do that, but what are the chances of hitting the pilots in the eyes, right? They are all flying on auto pilot anyway and won't be looking outside. So he tries to hit the plane with his laser. I'm not sure what Joe would actually see, as I've never pointed a laser at an airplane.

If Joe was actually shining with laser A, there would be no effect to the plane. The chances of hitting one of the eyes of the pilots are practically zero. It's a bit like the warning "don't use your cellphone while fuelling": theoretically possible that it might cause a disaster, but realistically speaking, nothing will happen.
However, Joe is shining laser B. The beam diverges, the chances of hitting the cockpit of the plane increase and the pilots get blinded, possibly with permanent damage to the eyes.

Note, if laser A would hit a pilot, the damage would be worse than laser B, as laser A would send ALL the energy in the eye. At least with laser B only a fraction shines in the eye if you get hit.

Allow me to bring up an anology: I have a typical revolver with one bullet in it. I am willing to pay you 10k if I can shoot at your head. You can be in bulletproof armor, but no helmet.
I offer you the money to shoot you from 2 meter distance. Would you take the deal? Maybe you should, as I am a lousy shot, but you probably won't.
I offer you the money to shoot you from 7000 ft while you are flying a bullet proof airplane (open cockpit though) at 180 kts. Would you take the deal? You'd at least consider it. The chances of me hitting your head are practially zero. That is how it looks from Joe Laser's perspective as well: he incorrectly assumes he is trying to hit a plane with a revolver instead of with a machine gun.

Yes you say, but it diffuses over distance right and they know that which is why they shine it at airplanes but not their kids eyes. But digits_ is saying they don't know it diffuses. So they don't know it diffuses, and they don't know it's dangerous. ER's must be full of people with laser blindness.

Diffuse means that light gets scattered when it interacts with other particles. I don't believe I used "diffuse" anywhere in this thread.

They know it is dangerous to the eyes. They know it is easy to hit your eyes from short distance. They don't think they are able to hit the eyes of the pilots from 7000 ft, as they incorrectly assume the light does not diverge.

There's more than meets the eye when it comes to lasers.

[Rockie]

Would Joe Laser who thinks he has the perfect laser point it near his kids or anybody else if he had any reasoning power between his ears? To believe they weren’t potentially dangerous he’d have to have gone through life never seeing a science fiction movie, never read a book, a newspaper, never watched tv, never heard of eye surgery or any of the thousands of other mentions of lasers in society.

He’s lived under a rock. Unlikely.

So he knows they can damage yet he points them at aircraft anyway. Sure digits_, educate them. That’s what Garneau’s announcement was supposed to do by telling them what will happen when they’re caught. Now let’s see if it works.

Here’s a thought experiment of your own. How many people go to court not knowing what they did was illegal and all they really needed was “education”?

[rookiepilot]

I see someone was up all night consulting a dictionary. Henceforth I will use the terms coherent and imperfect coherence to avoid confusing you.

Man you are rude and arrogant to those who don't agree with you.
I wonder if you talk that way to your superiors. I doubt it. Probably the exact reverse.

Just saying, Rockie.

[Rockie]

Man you are rude and arrogant.

You're right, that was uncalled for and I've removed it. I guess I was just reacting a little at having to open a dictionary myself to avoid using an incorrect term explaining a principle I clearly understand and isn't really the crux of the topic anyway.

Perhaps you should reread your own posts and be a little more introspective. Just a suggestion.

[digits_]

Would Joe Laser who thinks he has the perfect laser point it near his kids or anybody else if he had any reasoning power between his ears? To believe they weren’t potentially dangerous he’d have to have gone through life never seeing a science fiction movie, never read a book, a newspaper, never watched tv, never heard of eye surgery or any of the thousands of other mentions of lasers in society.
[...]
So he knows they can damage yet he points them at aircraft anyway.

Did you even read my post? Half of it deals exactly with question. It's about the probability of hitting someone with the perfect laser. In summary: close by, in the eyes: almost guaranteed hit, dangerous. At 7000 ft away: practically impossible to hit someone in the eye. See the gun analogy.

Sure digits_, educate them. That’s what Garneau’s announcement was supposed to do by telling them what will happen when they’re caught. Now let’s see if it works.

Here’s a thought experiment of your own. How many people go to court not knowing what they did was illegal and all they really needed was “education”?

They might know it is technically illegal, but if you don't tell them WHY or how dangerous it actually is, chances are people will ignore it. There are so many safety regulations and laws all around us, that some (most?) people have a habit of ignoring a lot of them if they don't understand why it is important.

[Rockie]

As I said, would you point a laser anywhere near your kid even if you thought there was little chance it might hit their eye? I'm guessing you wouldn't. But not everyone is as smart as you obviously. Pointing it at an aircraft is worse because of the very slight angular difference between the middle of the plane and the cockpit. Unless you have a foolproof gyrostabilized aiming system I'd say the chance of the beam crossing to the windows is even greater than up close. The proof is in how many reports there are of that exact thing happening. It happened to me so I'm not inclined to accept your supposition.

They might know it is technically illegal, but if you don't tell them WHY or how dangerous it actually is, chances are people will ignore it.

As I also said, unless you've been living in a cave cut off from the modern world your whole life it simply is not possible to not know lasers of any kind are potentially dangerous. People who get lasers play with them and very quickly discover the beam diverges and diffuses, most of the pointers do so within a room. Yet people still shine lasers at airplanes. Educate sure, but put some muscle behind it for the really slow learners of which there are many.

[digits_]

As I said, would you point a laser anywhere near your kid even if you thought there was little chance it might hit their eye? I'm guessing you wouldn't. But not everyone is as smart as you obviously. Pointing it at an aircraft is worse because of the very slight angular difference between the middle of the plane and the cockpit. Unless you have a foolproof gyrostabilized aiming system I'd say the chance of the beam crossing to the windows is even greater than up close. The proof is in how many reports there are of that exact thing happening. It happened to me so I'm not inclined to accept your supposition.

Well yes, that's the whole point: people are using laser B which makes it way easier to hit the plane, but they THINK they are using laser A which would be harmless. There is a discrepancy between what they THINK they are doing, and what they are actually doing. At short distance, the effect of laser A and laser B is the same, so they don't shine into their kids eyes. What happened to you was with laser B, not laser A, because laser A doesn't exist.

They might know it is technically illegal, but if you don't tell them WHY or how dangerous it actually is, chances are people will ignore it.

As I also said, unless you've been living in a cave cut off from the modern world your whole life it simply is not possible to not know lasers of any kind are potentially dangerous. People who get lasers play with them and very quickly discover the beam diverges and diffuses, most of the pointers do so within a room. Yet people still shine lasers at airplanes. Educate sure, but put some muscle behind it for the really slow learners of which there are many.

I am not disputing that lasers are dangerous, nor that they don't know that lasers are dangerous. Again, read my gun analogy.

Also, not sure what you mean with "the beam diffuses"?

[Rockie]

Also, not sure what you mean with "the beam diffuses"?

Does the light from a laser get refracted and reflected by moisture and other particles in the atmosphere?

[trey kule]

The penalties are the maximums. Not what has appeared so far in case law.

This is Canada. Brought before a judge, and found guilty, our laser pointer will, for the most part simply be told not to do it again. And if they do...well they will be told again, not to do it again.
Instead of 8 months, one or two well publicized 5 year sentences and a huge fine might offer a deterrent
I understand in the US this activity is taken much more seriously.

One of these boneheads will eventually bring down a plane and then we will see some judicial action occur.

[AuxBatOn]

What's the NOHD for such lasers?

A 2mm aperture, 200mW, 0.8 mRad beam divergence laser has roughly a 125m NOHD. You may be blinded by light but your eyes should be fine

[Posthumane]

A few years ago a friend of mine bought a 1W blue laser online for about $100, so they are quite accessible and easy for laymen to get. There weren't any controls on the site to keep minors from ordering it, as in most countries (at the time) buying high power lasers was perfectly legal. I don't have the specs on that particular laser, but it was able to light a piece of paper on fire from several metres distance. The divergence of course varies with the quality of the optical elements within the system - cheap laser pointers that you get from the dollar store do have enough that it's noticeable across the room, but with higher quality ones you might not be able to tell any difference in beam size until it got several hundred metres away (In fact some of the lasers tested at my workplace have a large aperture and convergent optics, focused for specific distances).

There are actually many cases of people going down to the park or other public places and shining these lasers at people passing by, including children. I used to get a weekly newsletter related to various weapon incidents, and at one time there were several instances a week within the US and Canada. They didn't typically make the news as often there was no physical harm done, although the potential was there. As AuxBatOn implies, the distance to cause permanent eye damage is not nearly as great as the distance where it poses a problem for pilots due to the dazzling/distracting effect of a bright light. The perpetrators in these cases were rarely caught and prosecuted.

There are definitely lots of people out there who like to intentionally cause harm, but I think there are many more (like digits points out) that really have no idea how dangerous these things can be. Do any of the non-technical people who buy these know why a blue laser is more dangerous to the eyes than a red laser? I think many of them don't, and probably don't care.

[B208]

Also, not sure what you mean with "the beam diffuses"?

Does the light from a laser get refracted and reflected by moisture and other particles in the atmosphere?

It gets reflected, refracted and absorbed by particles in the atmosphere, collectively known as "blooming". Even in a perfect vacuum it will start to diffract slightly when it leaves the appeture.

[photofly]

Coherent means that the wavelengths of the light are in phase. This is important for data transmission applications and lots of experiments. For our "blind the pilot" task, this is irrelevant (unless you are trying to beam updated SOPs through his retinas )\

Actually coherence is very relevant when it comes to stopping people seeing things. A coherent light source generates nothing but interference patterns with itself when it shines on objects, which makes it impossible to use it as a source of illumination for vision.

However, the coherence length of hand held lasers is short, in the tens of metres. Beyond that distance the laser is effectively no longer coherent.

[AirFrame]

One of these boneheads will eventually bring down a plane and then we will see some judicial action occur.

Sadly this is unlikely even if someone does bring down a plane. First off, the only way we'll know that a laser was the cause is if the pilot has time to make a call to someone and report the strike. Second, as with drones, finding the perpetrator on the ground has proved difficult if not impossible. And that's when they can play dumb and say "oh, well, nobody was hurt, see, my drone is back here in one piece". When they see an airplane hit the ground after the laser hit the airplane, they're going to be scared sh*tless and you'll never see them.