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Laser Pointers

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#1 Guest_**DONOTDELETE**_*

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Posted 04 March 2006 - 04:19 PM

I teach a very basic star gazing/constellation pogram at a camp I work at. I was looking into getting a laser pointer because the kids just don't seem to find that triangle shape or side ways M. I've been looking on EBay and I see some exprensive ones and some selling for 5 dollars. Money is an issue and I wasn't looking to spend much (we camp people make virtually no money) can anyone give me some basic knowledge on which type or even which grade to get? Any info would be helpful
Thanks

#2 Mattbtn

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Posted 04 March 2006 - 04:28 PM

Brighter, more powerful lasers will produce a beam that is much, much easier to see.

I've got a 1-3mw Orion that came with my XTi, and it doesn't really produce a beam that can be seen easily by people standing nearby, especially if the skies are somewhat light polluted.

On the other hand, I've seen lasers in the 15mw - 35mw range that cost in the $100-$200 range that are extremely easy to follow from several meters away.

Just remember, the more powerful lasers require more research on local laws, federal laws, etc... so be sure to check and make sure you won't get in trouble using it.

#3 Mitrovarr

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Posted 04 March 2006 - 04:42 PM

You'll want to check the laws yourself, but I think 5mw is the limit of what is generally considered legal. You can get more powerful ones, but you'd probably be in much worse legal trouble in the case of an accident (nailing a plane, etc.) The 5mw ones run about $100 or so.

On a side note, I'd be careful buying astronomy equipment off Ebay if you're just starting out; a lot of the stuff on there is junk and it takes experience to sort it out.

#4 erik

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Posted 04 March 2006 - 06:56 PM

i agree, get a 5mw laser- it's the brightest one available that's legal to use without special credentials. on most nights, 5mw is bright enough, although on dry nights of good seeing, the beam can appear dimmer. also, the cold affects a laser's brightness. i'd buy one from a reputable source that will allow a return or exchange. laser pointers aren't the heartiest pieces of equipment, besides the laser itself, the switches often go out...

#5 matt gray

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Posted 04 March 2006 - 09:26 PM

Howie Glatter makes a good one that is both legal, and easily seen for a hundred bucks.

#6 NeoDinian

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Posted 04 March 2006 - 09:39 PM

Brighter, more powerful lasers will produce a beam that is much, much easier to see.


Not completely true.. What you see is the result of the beam reflecting off the "Stuff" in the air. This can be dust, smog, etc.. But mostly moisture. Sure having a more powerfull laser will help you see more, but over 5mw and you run safety risks, as well as the possibility of a required license or permit to operate.

I've got a 1-3mw Orion that came with my XTi, and it doesn't really produce a beam that can be seen easily by people standing nearby, especially if the skies are somewhat light polluted.


Non collimated (Non-Tuned) lasers like this you run the risk of being on the LOW end of the scale. If you spend around 100-130, you can get a True, Tuned 5mW laser.

On the other hand, I've seen lasers in the 15mw - 35mw range that cost in the $100-$200 range that are extremely easy to follow from several meters away.


Due to the safety issues, as well as permits and licences possibly required for a Class IIIb laser, we should not be discussing them here. Without proper training, these can cause serious injury. These lasers are (In many areas) illegal to possess without those permits and Licenses also.

I'm still working on my Laser article about all this.. Had a small detour though since we've been looking at buying a house (and just had!) :)

#7 Mattbtn

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Posted 04 March 2006 - 09:51 PM

Thanks for the info Jeff...that's good to know. I haven't seen anything out there for my area discussing what is allowed and what is illegal.

Are those federal laws that limit anything above 5mw, or state/local laws?

#8 pietruck

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Posted 05 March 2006 - 12:39 AM

Brighter, more powerful lasers will produce a beam that is much, much easier to see.


Not completely true.. What you see is the result of the beam reflecting off the "Stuff" in the air. This can be dust, smog, etc.. But mostly moisture.



So how is this not completely true?

More powerful lasers require less dust, smog or moisture to be seen.

#9 MMICKELS

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Posted 05 March 2006 - 12:50 AM

What you see from a laser is the reflected light.

#10 pietruck

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Posted 05 March 2006 - 02:00 AM

What you see from a laser is the reflected light.


Right, mostly the laser reflects off of ambient moisture in the air. Hence what Eric said about dry nights making the beam look dimmer.

Eric also mentioned that cold will cause the beam to be dimmer. Laser pointers operate at their full output potential at an exact range of temperatures. When it is very cold they put out a dimmer beam this can be fixed by holding the laser in your gloved hand near the output end. Be careful not to accidentially turn it on. An armpit also works if your hands aren't warming it enough.

If you have the laser mounted on your scope there is not much you can do about it. I have yet to see a fix for this. JMI laser heater here we come ;)

#11 Jon Isaacs

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Posted 05 March 2006 - 10:28 AM

>>>I teach a very basic star gazing/constellation pogram at a camp I work at. I was looking into getting a laser pointer because the kids just don't seem to find that triangle shape or side ways M. I've been looking on EBay and I see some exprensive ones and some selling for 5 dollars. Money is an issue and I wasn't looking to spend much (we camp people make virtually no money) can anyone give me some basic knowledge on which type or even which grade to get? Any info would be helpful
Thanks
----

Hello and welcome to Cloudy Nights...

Here are some of the basics of laser pointers and astronomy:

1. You need a green laser rather than a red laser. The eye is very insensitive to red light so red laser pointer is barely visable. The eye is most sensitive to green light so what you need is a green laser pointer.

2. Safety and curteousy issues are important when using a laser pointer. Flash blinding is possible and can have lasting effects. Probably the best documented case is that of Gary Honis at the Cherry Creek Star Party. Last I saw, over a year later, his vision had not returned to normal. Around children, great care needs to be taken as I am sure you are well aware.

It is illegal in the United States to sell or promote Class 3B lasers as pointers or as amusement devices. A Class 3B laser is a laser over 5mw. Here is a link to the FDA website addressing Laser Pointers:

http://www.fda.gov/c...adhlth/lpm.html

Here is a quote:

""Can battery-operated, portable laser systems be sold in the U.S?

Yes, battery-operated, portable laser systems can be sold in the U.S., providing that they fully comply with the standard, are certified and reported, and are not Class IIIb lasers sold or promoted for pointing or amusement purposes.

People who operate Class IIIb portable laser systems should be familiar with the above ANSI standards for safe use of lasers. This ANSI series of standards includes specific information for the safe use of such laser products in their applications of use.

1. IEC – International Electrotechnical Commission Standard 60825-1, Ed. 1.2: 2001-08

2. ANSI Z136 standards are available from the Laser Institute of America (www.laserinstitute.org)""

I received my laser safety training in 1993 and have since been involved with several projects involving class 3B and class 4 lasers.

The guidelines for using a class 3b or class 4 laser require restricted access, safety eye wear etc.

Furthermore, use of a class 3b or class 4 laser outside with a group of people can qualify as a "Light show" and therefore require permits and certified training of the operators.

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Bottom line: Laser pointers are defined as being under 5mw. Anything over 5mw is not a pointer and should not be used as a pointer. A Class 3A laser can be effectively used as a tool to help teach others but must be used with care, particularly around children.

Also, since it is illegal to promote Class 3B lasers as pointers or amusement devices, it would seem that any suggestion of using a Class 3B as a pointing device here on Cloudy Nights could be considered as promoting the use and therefore illegal.

Please clean up your posts if you have suggested using lasers greater than 5mw as pointers.

Best wishes, clear skies...

Jon

#12 Jon Isaacs

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Posted 05 March 2006 - 10:34 AM

>>>>Thanks for the info Jeff...that's good to know. I haven't seen anything out there for my area discussing what is allowed and what is illegal.

Are those federal laws that limit anything above 5mw, or state/local laws?
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THere are both federal laws as to what can be sold as well as local and state laws. It is illegal to promote or sell a laser over 5mw as a "Laser Pointer."

http://www.fda.gov/c...adhlth/lpm.html

Jon Isaacs

#13 Guest_**DONOTDELETE**_*

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Posted 05 March 2006 - 10:41 AM

Thanks for all the info guys. I'm looking at getting the class IIIa, being that I work in Alabama and the humidity is almost all ways 95% I think I will be safe with that one. Thanks for all the help!

#14 Dubboy

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Posted 05 March 2006 - 10:58 AM

You may want to check out Luckyduck.com
They had a special a few weeks ago. Around $50

#15 snorkler

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Posted 05 March 2006 - 11:09 AM

Jon,

Thanks for the informative post about the law relating to lasers. I retired from the FDA, and you just saved me the trouble of encapsulating all that knowledge into a post ;) You might want to have someone sticky note this thread, or at least your message.

#16 NeoDinian

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Posted 05 March 2006 - 12:38 PM

Brighter, more powerful lasers will produce a beam that is much, much easier to see.


Not completely true.. What you see is the result of the beam reflecting off the "Stuff" in the air. This can be dust, smog, etc.. But mostly moisture.



So how is this not completely true?

More powerful lasers require less dust, smog or moisture to be seen.


Here is a better way of saying it...

You can have the most powerfull laser in the world.. But if your sky is absolutly clear of dust, smog, humidity, etc, you will NOT see that beam. The beam needs to be reflected off something to see it.

Yes, a more powerfull beam will be seen easier than a less powerfull one under the same conditions side by side... But a more powerfull one is NOT needed. If you get a TRUE 5mW laser, you will have NO problem seeing the beam under ANY conditions, world wide. There is always something in the air for the beam to reflect off. Cold weather is the only factor that will effed lasers now. Even your powerfull lasers will be effected, but not as much. But again, there are things you can do to limit those problems.

#17 pietruck

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Posted 05 March 2006 - 02:49 PM

Jon, you are clouding the definition of the word promote.

The word promote is in terms of sales in this useage.

It is not illegal for a private individual to suggest the use of something.

I can 'suggest" that is it fun to fire missles into the air. The act of doing so may be illegal.

I am curious why some people here are so quick to censor discussion, especially when it comes to lasers. The US military rates the threshold for permanent eye damage at 30mw. I feel that this is high personally. Most of these, brighter than 5mw leadlight brand green pointers fall in the 15-30mw range. They are VERY seldom capable of 50mw output (1 in 500 units are able to do this without frying).

There are other handheld lasers that go as high as 300mw. This is indeed dangerous and I often wonder who is buying these considering they are often more than $1500.

But I digress, I was jsut suprised that it was suggested that discussion of >5mw lasers is illegal. I tend to think it is best to offer good advice so that people know what they are getting into. That way we don't have accidents in the truest sense of the word.

Lastly, in response to neo's assesment. We do not live in perfectly dry or perfectly clean enviornments. To base your argument in a clean, dry non-existant vacuum is a falacy. Most of what lasers reflect off of is moisture. Some people live in much drier areas and for them lower power = less visibility.

Ryan

#18 Bob Griffiths

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Posted 05 March 2006 - 04:07 PM

Bottom Line: Should I even think about using a LOW POWER Green Laser as a pointer on my scope..?

Currently using a RACI Plus a Telrad..and there are times I
still have to almost stand on my head...The Green Laser would replace the Telrad (I think)...

I am also very concerned about aircraft..Live 60 miles from Both Dullas & BWI airports so I see aircraft quite allot..

And The Prez helicorpters right over the house on his way to Camp David...(20 miles away)...

Bob G.

#19 NeoDinian

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Posted 05 March 2006 - 04:58 PM

Ryan: The standard Class IIIa lasers, if tuned to the true 5mW are just fine in desert conditions. Been proven by users here at CN. And that Perfect environment scenerio is exactly my point. A Side by side comparison of Class IIIa and IIIb even in Desert conditions would show that both are very capable for our needs as amateur astronomers.

Bob: Being that close to Camp David, I would suggest you NOT look into a laser pointer. Either that, or possibly expect many supprise visits. :)

#20 Jon Isaacs

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Posted 05 March 2006 - 08:11 PM

>>>>But I digress, I was jsut suprised that it was suggested that discussion of >5mw lasers is illegal. I tend to think it is best to offer good advice so that people know what they are getting into. That way we don't have accidents in the truest sense of the word.
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NO has suggested that a discussion of using class 3B and Class 4 laser as pointer might be illegal, I have discussed them many times. You are well of aware of that.

I have discussed the safety issues, the ways that lasers can damage your eyes, the fact that it is illegal to sell or promote Class 3B lasers as pointers, the fact that anyone using a Class 3b laser should have taken the time to read the appropriate guidelines and take care to institute proper safety procedures (eye protection, access restriction are SOP). I have also pointed out that they should be aware that using a class 3B laser outside with a group of people may need to have a permit for a "laser light show."

If your interest is to inform then maybe you can take the time to discuss "flash blinding" and exactly how someone can still have vision problems more than a year later after being "accidentally" flash blinded at a star party by a Class 3A laser.

This would seem to be of importance as most are comfortable with using class 3A lasers as pointers.

...at the end of it all comes this webpage:

http://www.fda.gov/c...adhlth/lpm.html

Whether or not it is legal to use a Class 3b laser as a pointer, well, it is illegal to sell or promote such usage.

The fact that class 3B lasers cannot be sold as laser pointers makes the message clear.

Jon Isaacs

#21 Mattbtn

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Posted 05 March 2006 - 08:57 PM

Jon, although I understand your posts and your linkage to the FDA's website concerning Class IIIb lasers, I can't seem to find anything concerning the use by consumers. Every page I'm finding is directed towards manufacturers and generally indicate that lasers >5mw are NOT to be sold or promoted as laser pointers.

Now, that indicates as a manufacturer, you cannot promote or sell laser pointers >5mw for amusement or general purposes, but it doesn't say anything about people who actually purchase these lasers and use them for those purposes anyways.

The only thing from the FDA I could find regarding consumer purchasing is that they might lose the $ for their laser, as it is very possible it could be confiscated by the US Customs & Border protection.

Now, this is merely a technicality, but I guess I'm looking for a more clearcut answer on this issue regarding the more powerful lasers and the use of them by consumers, for whatever reasons.

#22 Pat1

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Posted 05 March 2006 - 11:04 PM

Hi everyone,

I few years ago I was to work with a class IV Nd:YAG at a federal center. I seem to recall in the "Laser Safety Exam", any 'visible' laser that exceeds 5mW (or 5mJ per pulse) required additional safety measures to operate legally. This requirement is more stringent for IR beams. Ours, being a class IV, required it to be enclosed and with all kinds of bells and whistles. Of course, it took almost a year of pre-approvals and hoop-jumping to finally get down to business.
All this was due to federal regulations, city or state laws had no effect. We already had the laser (inherited in non-working conditions), but we weren't allowed to use it. Unfortuneatly, I don't know what paperwork had to be done when the laser was first purchased.

Regrading safety, every now and again, we recieve emails with laser accident reports; smart people can sometimes make boo-boos.


The US military rates the threshold for permanent eye damage at 30mw.



Hi Ryan,

to me, the above statement seems a little loose. Do you have a reference at hand? I'm curious to know what type of eye damage and the duration or number of pulses.

Thanks in advance :)

#23 Jon Isaacs

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Posted 06 March 2006 - 09:17 AM

<<<Now, this is merely a technicality, but I guess I'm looking for a more clearcut answer on this issue regarding the more powerful lasers and the use of them by consumers, for whatever reasons.
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This is the most clear-cut answer I have found. It is illegal to promote or sell a laser above 5mw as a pointer in the US. In my view, that makes it pretty clear. In addition, there are safety standards and guidelines as well which discuss Standard Operation Procedures for class 3B and Class 4 lasers and the FDA says that anyone operating a laser above 5mw should be familiar with these. Eye protection and controlled access are the name of the game here. Furthermore, outside operation of a Class 3B or Class 4 Laser would seem to be a "Laser Light Show" and thus require permits.

All in all, the message seems quite clear to me, lasers are not toys, they have the capability to harm others at a distance and there are regulations regarding the sale of them as pointers...


For anyone who has not looked at the FDA page, here is one section:

"""Are Class IIIa laser pointers dangerous?

Class IIIa or IEC Class 3R lasers can be dangerous. Class IIIa lasers can cause temporary visual effects such as flash blinding, which could distract or startle the person exposed. The risk of injury is very small when Class IIIa pointers are used responsibly because natural body motion of a person holding the pointer or motion of a person who might be exposed makes it difficult to expose the eyes for a long period of time. People also have a natural aversion to bright lights and are likely to close their eyes and turn their heads if exposed.

What are class IIIb lasers and are they dangerous?

Lasers that emit between 5mW and 500mW output power are in Class IIIb or IEC Class 3B. Class IIIb lasers cannot legally be promoted as laser pointers or demonstration laser products. Product labels and user instructions must describe the hazard classification of the product and its output characteristics.

With any laser product, the potential for injury depends both on the product itself and how the product is used. Higher powered Class IIIb or IEC Class 3B lasers are dangerous and can cause either temporary visual effects or an eye injury.

What is the problem with more powerful Class IIIb lasers being promoted and sold as pointers?

Class IIIb hand-held lasers are too dangerous for use as pointers or amusement articles. Furthermore, promotion of Class IIIb or IEC Class 3B products for pointing or amusement violates FDA requirements and United States law. Manufacturers of such products may be required to repair, replace, or refund the purchase price of violative products distributed in the U.S. These products are also subject to detention and seizure by the U.S. Customs and Border Protection when imported.

Irresponsible use of more powerful laser pointers poses a significant risk of injury to the people exposed. Persons who misuse or irresponsibly use lasers are open to personal liability and prosecution.

What are the FDA requirements for Class IIIa and IIIb laser systems?

The FDA standard 21 CFR 1040.10 and 1040.11) requires a warning label on Class IIIa and IIIb products. Class IIIb products must also have a key switch and connector for remote interlock. The products are also required to have identifying and certifying labels and instructions for safe use.
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Seems the message here is quite clear even if the law may have "technicalities."

Jon

#24 snorkler

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Posted 06 March 2006 - 10:14 AM

I think of it as a liability issue. There may not be anything specific that says a customer can't buy a 70 mW laser off of eBay and use it to dazzle the neighbors. But if someone gets blinded because that laser didn't have interlocks, or because the user pointed the beam into a nearby office building, or because it lacked the required shielding, guess who's going to lose his house and car to pay the legal liability from the resulting lawsuit? Consumers without training or knowledge of the safety requirements who buy light show lasers are similar to kids taking daddy's .38 Special to school to show it to their friends. There's nothing illegal about the manufacture or ownership of the item, but plenty of potential problems in its proper usage.

The liability issue is why I kept my 5 mW laser pointer at 5 mW instead of buying one modified to put out 10 mW. It's a lot easier to explain an accident using a legal item (the IIIa 5 mW laser) than one using an illegal item (the IIIb 10 mW laser). If you think it's legal to own a 10 mW laser, you're right. If you think a modified 10 mW handheld laser is legal, you're wrong. Where's its safety interlock, keys, shields, etc? How many of the 30, 70, and 100 mW lasers on eBay have those features? I haven't seen a one pictured that looks like it bears the required warnings, certifications, manufacturer declaration, or safety features.

The opinions expressed herein are mine, and they should in no way be construed as being or representing the views or opinion of my former employer.

#25 NorthCoast

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Posted 06 March 2006 - 10:43 AM

I think anyone that has seen a tuned 5mW laser would have no problem limiting the power to just that... I have seen $5 specials next to a real 5wM pointer and it was clear to me that the 5mW is enough - enough not to have one in the house with my two small children. I am not against laser pointers, and, as a teaching aid there my be some real value; however, just look at the adds (and sites) that promote the greater than 5mW devices. "Let's light some matches and send signles to our buddies across the city..." Then put a footnote to "use responsibly" and "check applicable federal and local laws". That scares me!


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