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laser pens


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Hi can some one advise me on green laser pens,i bought one of ebay which isjust a dot no beam what so ever.Prob not the best of plces to go to,so what is a sensible price to pay and where to go please

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can I ask, why would you expect there to be a beam? 

Just as with a torch, you'll only really see a beam if the light is passing through something that's diffusing it, like mist or smoke.

added:
Don't know if you recall a time when Oxford Street spent a fortune putting a laser light display up instead of the traditional lights?

It was deemed a flop because you didn't see the beams tracking, tho I was lucky to walk along one evening when it was drizzling, it looked way better than on a dry night :) 

Edited by DaveL59
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Laser pen /pointers are for indoor use, for pointing at Powerpoint presentations etc  on a projection screen.

So you only need a green dot on the screen, beam not necessary.

Some people buy illegal high powered ones they use at night, these can blind airline pilots, you don't want one of those.

Michael

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There are eight (8) classes of laser products according to British Standard. They range between Class 1 and Class 4.

Health and Safety regulations place restrictions on lasers above Class 2 (<1 mW).

The laser provided with your barndoor is 5mW

You're absolutely right, insane beam, these can blind airline pilots.

Southampton has an airport, so do us all a favour.

Michael

 

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9 hours ago, michael8554 said:

There are eight (8) classes of laser products according to British Standard. They range between Class 1 and Class 4.

Health and Safety regulations place restrictions on lasers above Class 2 (<1 mW).

The laser provided with your barndoor is 5mW

You're absolutely right, insane beam, these can blind airline pilots.

Southampton has an airport, so do us all a favour.

Michael

 

Thanks Michael, i did not know, looks like ill be replacing the laser then, why an earth would they ship these with it?

 

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Any laser below 5mW is considered "eye safe" in that your blink response will protect against any damage, our eyes are blasted by lasers at around 5mW  (infra red variety) every time we drive down a main road.

Alan

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We were shown round an Air Ambulance base not long ago.

Apparently the laser light is refracted into the curved plastic windscreen and the whole forward view is obliterated.

Literally flying blind.

Even after the laser has stopped they are obliged to land ASAP and cannot fly again until their eyes have been tested.

Michael

 

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3 hours ago, DaveL59 said:

can I ask, why would you expect there to be a beam? 

Just as with a torch, you'll only really see a beam if the light is passing through something that's diffusing it, like mist or smoke.

added:
Don't know if you recall a time when Oxford Street spent a fortune putting a laser light display up instead of the traditional lights?

It was deemed a flop because you didn't see the beams tracking, tho I was lucky to walk along one evening when it was drizzling, it looked way better than on a dry night :) 

To be honest i saw one used at my astronomy club it had a nice wide beam.As j am pretty much new to astronomy  my idea was to put the laser on my scope as a aid to my view finder then turn it of when found that is why i bought this one.

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5 hours ago, djs44 said:

To be honest i saw one used at my astronomy club it had a nice wide beam.As j am pretty much new to astronomy  my idea was to put the laser on my scope as a aid to my view finder then turn it of when found that is why i bought this one.

yikes, in your location I'd not advise pointing a laser into the skies, especially once aircraft are back operating. You might be careful but a pilot reporting a laser beam could well result in a visit from the boys in blue. Endangering an aircraft is a pretty serious one to get pulled on. As Micheal above has said, lasers cause major problems for pilots and in areas near an airport where planes are typically taking off or landing, losing vision the last thing a pilot needs. I used to be a manager at an airport in a built up area where VFR (visual flight rules) was the only way to operate, a pilot losing vision there could be very serious given the tall buildings and steep approach.

Do you not have a red dot finder on your scope? That should get you reasonably onto target if its properly aligned. If you want to upgrade it to something better then a telrad or rigel one are well recommended, or if you prefer a decent finderscope.

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9 hours ago, michael8554 said:

We were shown round an Air Ambulance base not long ago.

Apparently the laser light is refracted into the curved plastic windscreen and the whole forward view is obliterated.

Literally flying blind.

Even after the laser has stopped they are obliged to land ASAP and cannot fly again until their eyes have been tested.

Michael

 

why would any company keep using that material if it refracts the laser to the point of being completely blind, especially a medical vechile? you would think they would take every precaution

 

rest assured my barn door will not be in use till this beam laser is removed

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10 hours ago, Alien 13 said:

Any laser below 5mW is considered "eye safe" in that your blink response will protect against any damage, our eyes are blasted by lasers at around 5mW  (infra red variety) every time we drive down a main road.

Alan

No, visible-wavelength >1mW <=5mW is a class 3R laser, which is not eye safe by default. 3R requires special handling to maintain eye safety.

In practice, both class 3R and 2 lasers won't cause any eye safety issues if diffused by a windscreen even a bit at the sorts of distances involved due to optical path loss in free space but the bright light it would create would of course distract which is normally the main issue. That doesn't stop a class 3R laser being dangerous to handle on the ground, though. For reference once your organisation goes above handling class 2 lasers you need a designated trained laser safety officer if you're operating commercially - class 3R is well into the realm of stuff that can cause permanent eye damage.

8 minutes ago, tingting44 said:

why would any company keep using that material if it refracts the laser to the point of being completely blind, especially a medical vechile? you would think they would take every precaution

 

rest assured my barn door will not be in use till this beam laser is removed

Windscreens get scratched. Scratches diffuse and stop total internal reflection. Almost all aircraft windows are plastics rather than glass for weight and safety reasons, and dust and dirt will over time pit and scratch any surface.

High powered laser pointers are technically legal in many jurisdictions and enjoyed by some enthusiasts and laser hobbyists but definitely aren't suitable for normal outdoor usage - they're for safely controlled use in a shielded setting and require the use of safety goggles etc.

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1 hour ago, tingting44 said:

why would any company keep using that material if it refracts the laser to the point of being completely blind, especially a medical vechile? you would think they would take every precaution

The choice of materials is driven by a number of factors, such as impact resistance, transparency etc. I expect you may find that if someone aimed a laser into your car at night you'd end up in a similar position, with the glass reflecting it all over the place. Same result with a plane too. Its unfortunate really that these "toys" fall into the hand of the irresponsible and very fortunate that there's not been a major accident as a result. Not saying an astronomer who'd like to use one for brief aiming is such but there's a lot of care needing to be taken and an awareness that stuff like online flight trackers have a lag so you can't really rely on those to give you a confirmation that where you plan to aim is really clear.

Edited by DaveL59
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The regulations about laser pointers are different in different countries, so make sure that you are informed about the specific regulations that apply to you.

Most cheap green lasers pointers are extremely dangerous. Some of them are way more powerful than 5 mW, even if the label says otherwise. All cheap green pointers are 532 nm lasers, and they have unseen but very dangerous infrared 'leakage' by design. IR filters are often missing.

So, if you really think you need a laser pointer, buy from a reputable dealer, make sure they are certified to the power advertised, make sure a proper IR filter is installed or buy a 515 or 520 nm green laser that has no infrared leakage, and use them wisely only when there is no airline traffic, never point at people and don't play with them. Heck, what I really want to say: don't buy one, don't use one. It's just too dangerous.

Here's an interesting write-up about the dangers of laser pointers.

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i understand now, thanks for explaining, i got to say i knew the basics about a laser, not to shine in eye, not to shine at aircrafts, but i have learnt an awful lot from this thread! they are so so dangerous i just wish there were more precautions in place for the sellers and buyers tbh, and shipping such lasers with a mount designed for AP where its pointing towards the sky seems crazy to me :(

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unfortunately a case of lack of good enforced regulation, esp UK always so slow to do anything on stuff like this. Problem is also inconsistent regs globally where in some you can happily point a laser upward and not care at all. But even with regs in place, when you add in the ease that you can order stuff online from overseas etc, sadly rules get bypassed and those manufacturers and sellers don't really care in the main, income is king and all that...

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2 hours ago, DaveL59 said:

yikes, in your location I'd not advise pointing a laser into the skies, especially once aircraft are back operating. You might be careful but a pilot reporting a laser beam could well result in a visit from the boys in blue. Endangering an aircraft is a pretty serious one to get pulled on. As Micheal above has said, lasers cause major problems for pilots and in areas near an airport where planes are typically taking off or landing, losing vision the last thing a pilot needs. I used to be a manager at an airport in a built up area where VFR (visual flight rules) was the only way to operate, a pilot losing vision there could be very serious given the tall buildings and steep approach.

Do you not have a red dot finder on your scope? That should get you reasonably onto target if its properly aligned. If you want to upgrade it to something better then a telrad or rigel one are well recommended, or if you prefer a decent finderscope.

Thank you for that info,i will change finder scope,going to take a look at telrad.As for the laser pen am going to bin that.

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Ref @WaddenskyThank you for the link. Very informative and a good warning.

I own various stand alone lasers. Infra red, red, and green. Also a cheap laser engraving machine.
Low power scope collimating lasers are fine. As are presentation pointers and laser 'spirit' levels. Assuming they have come from a known manufacturer who will ensure the power is appropriate.
For anything else, extreme caution is advised.

I have never found the need for a laser pointer on a scope as a finder, for personal use.

My £100ish engraving machine (allegedly 1500mW but who knows) happily burns wood, paper, plastics, etc.
This is a definite safety glasses on (for the laser wavelength), stop and turn off the laser to check progress, and nobody else in the room.

Think of a laser like a gun. They may not harm you while taking precautions. But the projected light (bullet) can harm at a distance. 
Like a bullet hit, your eyes can be permanently damaged by a single hit.

 

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12 minutes ago, Carbon Brush said:

Ref @WaddenskyThank you for the link. Very informative and a good warning.

I own various stand alone lasers. Infra red, red, and green. Also a cheap laser engraving machine.
Low power scope collimating lasers are fine. As are presentation pointers and laser 'spirit' levels. Assuming they have come from a known manufacturer who will ensure the power is appropriate.
For anything else, extreme caution is advised.

I have never found the need for a laser pointer on a scope as a finder, for personal use.

My £100ish engraving machine (allegedly 1500mW but who knows) happily burns wood, paper, plastics, etc.
This is a definite safety glasses on (for the laser wavelength), stop and turn off the laser to check progress, and nobody else in the room.

Think of a laser like a gun. They may not harm you while taking precautions. But the projected light (bullet) can harm at a distance. 
Like a bullet hit, your eyes can be permanently damaged by a single hit.

 

Hey, I also own a few high power lasers. I was working on building an arduino laser harp and have experimented with various lasers and wavelengths including a 300mw Green and a 300mw white(RGB).

The RGB is most definitely the most dangerous as most goggles only block certain wavelengths and have found myself wearing multiple goggles with that one.

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