Laser Pointer Usage for Outreach
The RASC provides training to its members on the safe usage of laser pointers for astronomical outreach. For details on the program and certification process, check out our Program Guide. Note that to access some items linked in the Program Guide, you must be certified as a Centre Trainer or National Instructor. More information about our Laser Pointer Certification Program is included below.
Certified Laser Pointer Users/Spotters must fill out this form after an event at which laser pointers were used. You must be logged into your member account to access the form.
Over the last decade, the striking ethereal glow of laser pointers (sometimes referred to as Green Laser Pointers, or GLPs) has become a familiar sight at astronomy education and public outreach (EPO) events, from star parties for beginners to sky-at-night tours around astronomical installations. With the beam of a laser pointer an astronomy educator can direct an audience unerringly to a specific object - planet, meteor-shower radiant, star, asterism, constellation, or nebula. The very light of the laser pointer itself can seem to confer an enhanced authority on the EPO instructor. The laser pointer remains one of the coolest tools in the amateur's instrument case - but only if used responsibly. Laser pointers are tools not toys, and their misuse can lead to serious harm.
Under the Canadian Aeronautics Act, conviction for laser flashing an aircraft carries maximum penalties of a five-year prison term, and a $100,000 fine:
https://tc.canada.ca/en/campaigns/aiming-laser-aircraft-not-bright-idea.
The RASC counsels its members at all times to cooperate with law enforcement officials, and to remain within the law.
It is the Centre's responsibility to ensure that all laser pointer users and spotters are trained according to RASC guidelines.
The RASC has worked with Transport Canada to ensure laser pointer use for astronomical purposes is legal and safe. The RASC has authorisation from Transport Canada to train and certify our members to safely and legally use laser pointers for astronomy. Any individual, RASC member or otherwise, can use a laser pointer for astronomy provided they either:
- Follow Transport Canada's requirements, available on the Transport Canada website. These requirements include filling out a form and receiving written permission from Transport Canada to use a laser pointer for astronomy.
- Become certified as a laser pointer user/spotter with the RASC and follow the rules and requirements outlined in the program.
In keeping with the RASC's commitment to informative, inspiring, and safe EPO, members are required to complete Laser Pointer User/Spotter training before using a laser pointer at an RASC event. Laser Pointer User/Spotter training goes over the basic rules a user/spotter must follow when using a laser pointer and tests future users/spotters' knowledge with an exam at the end of the course. The rules users/spotters must follow include, but are not limited to:
- Ensure that laser pointers are operated only by certified users. Users must be over the age of 18 and a member of the RASC for two or more years to be eligible to take Laser Pointer User/Spotter training. Every event at which a laser pointer is used must also have a spotter to ensure the laser is not being used near aircraft.
- Do not to shine laser pointers in the direction of any person, vehicle, aircraft, or wildlife;
- Avoid using laser pointers near an airport or airport runway approach. Transport Canada requires that laser pointers not be used within 10km of an airport, or within the greater metropolitan areas of Vancouver, Toronto and Ottawa;
- Use the minimum power to do the job, and do not use a laser over 5mW in power.
- Be aware that distraction and distress can be experienced by anyone illuminated by laser light, even if the level is well below that which would cause physiological damage;
- Use good sense in storing laser pointers. Don't leave lasers accessible to children. Consider removing the batteries when you are done using a laser pointer.
- Follow protocol by receiving approval for laser pointer use at a given event from your Centre Executive, and fill out the required report after your event.
By following these rules, RASC members will reduce the chance of an unfortunate incident involving laser pointers, and will demonstrate due diligence while leading public astronomical activities. To become a certified user/spotter, contact your Centre.
Remember, laser pointers are useful if you're SMART about using them.
Safe = place safety foremost
Mature = keep laser pointers in responsible hands
Astute = use laser pointers skilfully and economically
Rational = match your laser pointer use to your scientific approach
Tactical = think ahead - plan your laser pointer use
These guidelines and the materials on this page were created by the RASC's former Green Laser Pointer Committee.
The Intensity, Luminance, and Illuminance of Laser Pointers
by Roy Bishop
I note in the recent flurry of emails on Green Laser Pointers, that some people seem to underestimate the hazard these devices pose if aimed at someone, particularly from a distance of several kilometres. I did some calculations for my 5 milliwatt green laser and arrived at these results:
Intensity = 3.8 x 106 cd (candelas)
Luminance = 5 x 1012 cd/m2 (candelas per square metre)
To put the latter number into perspective, the luminance of the surface of the Sun = 1.9 x 109 cd/m2, so my green laser has 2,600 times the luminance (surface brightness) of the Sun.
The power required to light an incandescent light bulb (sending light in all directions) that appears as bright as my green laser (when aimed at someone) = 3 megawatts (Three megawatts will power a sizeable town).
At a distance of 3.5 km my green laser will provide the same illuminance (surface illumination) as does the full Moon.
From a distance of 320 km (for example, from the ISS) my green laser will appear as bright as the planet Jupiter (neglecting atmospheric absorption). Thus, at "everyday" distances (several kilometres or less) a 5 mW green laser is going to be damn bright, and a major hazard to anyone whose attention is needed elsewhere, like a pilot or the driver of a car, especially at night.
It is the extremely small divergence of its beam that gives the laser these impressive figures.
And mine is only a 5 mW laser. 600 mW (!) hand-held green lasers are being advertised for sale to the public, few of whom understand physical concepts like solid angles and luminance.
If anyone would like to check my results, here is the input information:
- Power: 5 milliwatts (Advertised)
- Beam diameter at the laser: 1.0 millimetre (I measured it.)
- Beam divergence: 1.0 milliradian (Twice the half-angle) (I measured it.)
- Wavelength: 532 nanometre (Advertised, and I measured it.)
At the wavelength of the peak sensitivity for bright-adapted (photopic) vision (555 nm): 1 watt produces 683 lumens (p. 36 of the Observer's Handbook).
At a green laser's wavelength (532 nm), the response of the eye is about 0.88 as great (p. 70, Observer's Handbook).
Sun's radius, power, and luminous intensity: p. 34 Observer's Handbook.
Photometric efficiency of an incandescent light bulb: p. 36 Observer's Handbook.
For the illuminance provided by a light source of a certain visual magnitude: p. 35 of the Observer's Handbook.
For the visual magnitude of the full Moon: p. 35 Observer's Handbook.
For the relations between the units lm, cd, lx, and sr: p. 36 of the Observer's Handbook.
These resources were developed by the RASC's Green Laser Pointer (GLP) Committee 2010-2013
R.A. Rosenfeld, Chair (National Member)
Chris Beckett (National Member)
Dr. Roy L. Bishop, FRASC (Halifax Centre)
Mike Hanes (London Centre)
Dr. Paul Schumacher (Victoria Centre)
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