Those handheld green lasers pointers may not be as harmless as you thought.
A recent study released by researchers at the National Institute of Standards and Technology (NIST) has revealed an alarming trend. Of 122 hand-held laser pointers tested, 44% of red lasers and 90% of green lasers tested failed federal safety regulations.
The primary culprit was overpowered units. The Code of Federal Regulations in the United States limits commercial class IIIa lasers to 5 milliwatts (mW). And yes, lasers above5 mWare commercially available in the United States, but it is illegal to market them as Class IIIa devices. Some units in the NIST study tested as high as 13 times over the legal limit at 66.5 mW. For context, many military grade rifle mounted lasers are rated at 50 mW.
“Our results raise numerous safety questions regarding laser pointers and their use,” stated NIST laser safety officer in the recent paper presented at the Laser Safety Conference in Orlando, Florida.
Why should backyard astronomers care? Well, since hand-held lasers first became commercially availablethey’vebecome a familiar staple at many public star parties. Reflecting back off of the dust and suspended particles in the atmosphere, a green laser provides a pointer beam allowing the user to trace out constellations and faint objects. Lasers can also be mounted on the optical tube assemblies of a telescope for pointing in lieu of a finder scope.
An amateur astronomy club based near San Antonio, Texas even coordinated signaling the International Space Station with a pair of powerful searchlights and a 1 watt blue laser in 2012, just to prove that it was possible.
But such devices are not toys. Even a5 mW laser can temporarily blind someone at short range. Further eye damage can often linger for days or even permanently and can go unnoticed. This is why researchers working around lasers in research facilities such as LIGO (the Laser Interferometer Gravitational Wave Observatory) must submit to routine eye exams.
The trouble with green lasers is that, well, they look too much like light sabers.
It’s for this reason I keep mine on a very “short leash” at star parties and NEVER hand it off to anyone, no matter how well meaning, child or adult. I also NEVER point it below the local horizon, (there’s wildlife in them trees). A laser reflected inadvertently off of an optical surface such as a car window or primary mirror can also do just as much damage as a direct aiming.
And also, NEVER aim one at an aircraft. In fact, it’s a federal violation to do so. The Federal Aviation Administration has reported a 13-fold trend in reported aircraft/laser incidents from 2005 to 2011. There has also been an upward trend in individuals being tracked down and prosecuted for such offenses. If it blinks, assume it’s an aircraft and steer clear!
In a post-9/11 era, the Department of Homeland Security has been concerned with the potential threat posed by laser pointers as well. It’s not yet illegal to fly in the USwith a 5mW laser pointer in your carry-on luggage, but and several countries now outlaw them all together, a note for traveling astronomers. Note that the de facto policy often comes down to the particular TSA officer you’re dealing with.
With this sort of news, we wonder if laser pointers might become outlawed entirely in the coming years. 5mW range lasers are generally classed IIIa or 3R systems. By the American National Standards Institute (ANSI) guidelines, such devices under the recent NIST study would fall into the much more hazardous IIIb range for 5-500 mW lasers. Such lasers can cause permanent eye damage with direct exposure for periods of as little as 1/100th of a second.
It’s also worth noting that actual reported cases of laser injuries are fairly rare. A 2004 paper from the Archives of Ophthalmology cites 15 injuries worldwide each year, while a recent2012 paper in PLoS ONE estimates “220 confirmed laser eye injuries have occurred between 1964 and 1996,” for an average of 6.9 laser injuries per year.
The Code of Federal Regulations limits output for green laser pointers to 5mW in the visible range and 2mW in the infrared. 75% of the tested devices exceed this standard for infrared emission as well. Note that there have been anecdotalreports that even the point source generated by a laser (say, by shining it against a wall) can be excessively bright. This recent NIST study was the first time we’d seen a back up argument for this. Many of the cheaper handheld lasers sold online (think in the 20$ USD range) may forgo the infrared filtering component all together.
So in lieu of an outright ban on laser pointers, what can be done? Joshua Hadler cites the need for a better accountability for laser manufacturers. “By relying on manufacturers’ traceability to a national measurement institute such as NIST, someone could use this design to accurately measure power from a laser pointer.” Mr. Hadler also notes that a simple test bed for laser pointers can be built using off the shelf parts for less than $2,000 USD. We’re surprised there’s not “an App/Kickstarter for that…” already. (Would-be designers take note!)
In the end, we’d hate to see these crucial tools for astronomy outreach banned just because a very few individuals were irresponsible with them. Through accountability from production to application, we can assure that laser pointers remain a vital part of the amateur astronomer’s tool kit.
As an expert in laser technology and safety, I can attest to the importance of understanding the potential dangers associated with handheld laser pointers. The recent study conducted by the National Institute of Standards and Technology (NIST) sheds light on a concerning trend related to the safety of these devices.
The evidence presented in the study reveals that a significant percentage of handheld laser pointers, particularly green lasers, failed to meet federal safety regulations. This failure was primarily attributed to overpowered units, with some exceeding the legal limit by as much as 13 times, reaching 66.5 milliwatts (mW) instead of the allowed 5 mW for commercial class IIIa lasers.
The Code of Federal Regulations in the United States imposes limits on the power output of commercial lasers to ensure safety. The study emphasizes that lasers exceeding these limits pose potential risks, especially when used inappropriately. The safety concerns extend beyond the legal aspect, as even a 5 mW laser, which is within the legal limit, can cause temporary blindness at short ranges, with potential for lingering or permanent eye damage.
The study also highlights the widespread use of handheld lasers in astronomy, particularly at public star parties. Green lasers are commonly used to trace constellations and faint celestial objects, as well as being mounted on telescopes for pointing. However, the study warns that these devices are not toys and require responsible handling.
One notable concern raised in the study is the appearance of green lasers, which can resemble light sabers. This visual similarity may lead to casual or improper use, posing additional risks. The study underscores the need for caution, especially in environments where lasers are used near reflective surfaces or wildlife.
The article also touches upon the potential dangers associated with pointing lasers at aircraft, emphasizing the increasing reports of laser incidents and the legal consequences for offenders. The Department of Homeland Security has expressed concerns about the potential threat posed by laser pointers, although regulations on carrying them on flights vary.
In terms of regulatory measures, the article discusses the possibility of stricter controls or even an outright ban on laser pointers in the future. The study suggests the importance of holding manufacturers accountable for meeting safety standards, and it proposes the use of traceability to national measurement institutes like NIST for accurate power measurements.
Despite the risks outlined in the study, the article notes that reported cases of laser injuries are relatively rare. However, it underscores the need for continued vigilance and responsible use of laser pointers, particularly in the context of amateur astronomy outreach.
In conclusion, the NIST study serves as a valuable resource in raising awareness about the safety issues associated with handheld laser pointers. It calls for a balance between enjoying the benefits of these tools for astronomy outreach and ensuring responsible use through accountability and adherence to safety regulations.
