If you own a pocket-sized laser or you’re planning to invest in one of the trendier laser gadgets on the market now, you’ll likely be wondering, just how far can laser pointers go? And, is there a point at which your blue beam or green laser pointers reach their maximum distance?
Knowing as much as you can about what you can get from the output of laser pointers can help you not only make better use of these handy little devices but also understand how they work a little better.
With this in mind, we’ll be taking an in-depth look at everything from what laser pointers are to how far the beams of light they project can travel.
What are Laser Pointers?
Laser pointers are small, handheld devices powered by a battery and a laser diode that emits a concentrated beam of light. The visible beam is shot at a specific output power level on a precise wavelength.
Lasers come in different shapes and sizes and the visible laser beams may appear red, green, violet, yellow, or blue.
The word “LASER” is in fact an acronym for Light Amplification by Stimulated Emission Radiation. However, most modern lasers in use today don’t employ light amplification technology. As such, they aren’t technically lasers. But even with this, monochromatic lasers still carry that name tag.
Essentially, the main function of this electromagnetic device is to make specific objects or details more distinct.
Laser beams can be adapted for use in various ways. For example, the light source has become very popular as a presentation aid. Meanwhile, more powerful lasers which are several times brighter are employed to present the ideal conditions for stargazing at the night sky.
How Far Can Laser Pointers Go?
How far laser pointers can go depends on how powerful the output powers of the laser are and its artificial light wavelength. This is why more powerful laser beams are easier to see across farther distances. The power a laser pointer gives off is calculated in milliwatts (mW) or Watt (W).
1 milliwatt (mW) handheld lasers have a 2,139 to 4,555 square meter wide travel distance. A 1W laser pointer has an even greater range. It’s worth noting though that the higher the power of the laser beams, the greater the divergence.
However, due to the potential dangers that more high-power laser pointers pose, their public use isn’t actively encouraged. The United States Food and Drug Administration set the legal limits of the output of laser pointers at 5 milliwatts maximum.
However, even green light and blue laser pointers that conform to these standards can still reach surprisingly far distances. These gadgets have even been implicated in attacks on airplane pilots over the years.
Because of these incidents, lasers are now regarded as something of an electronic weapon and their use in aircraft distances has become punishable by law.
Is it Possible for Average Laser Pointers to Reach the Moon?
No, an average laser pointer cannot reach the moon. The main reason for this is that its beam isn’t sufficiently powerful enough to travel such a distance. Visual interference distance and several other variables also factor into the limitations of regular laser pointers here.
However, in theory, more powerful lasers should be able to cast a dot of light on the surface of the moon. But, for this to happen successfully, the laser beams must be used under the most ideal conditions.
Laser Pointer Specifications
Laser pointer specifications refer to those variables that influence the operation and performance of these gadgets to varying degrees. Basically lasers are dependent on each of these elements to ensure their full functionality. These specifications include:
Laser Wavelength
The artificial light wavelengths that a laser beam travels on is what determines the color that the human eye perceives. Technically, all lasers can produce both infrared and ultraviolet light. But, the projection of laser pointers is specifically confined to the visible spectrum.
The main reason for this is because that’s the only way that the human eye can understand and utilize the output power of laser pointers.
Laser Color
This factor is intricately tied to wavelength. But it’s a unique variable in its own right because it strongly influences the simplicity or complexity of your laser pointer.
As an example, red laser pointers are very common because it’s relatively easy to get a 671 nm laser diode. Also, these pointers may not need more than some good batteries and a simple lens through which the output beam will be collimated to start working.
All of this can happen because the 671 nm laser diode has an output that falls comfortably with the red spectrum.
On the other hand, a green pointer requires the introduction of more complex aspects of laser technology to create. The main reason for this is that diodes that emit an output within the green spectrum are in scarce supply.
The process is even more complicated if violet and blue beams that travel a visible distance are to be created.
Here’s a table highlighting basic laser colors, their attributes, and specifications.
| S/N | Laser Color | Laser Wavelength in nm | Average Power | Features |
| 1. | Violet | 390 – 455 | Above 12mW | May appear blue to the naked eye due to its closeness to the ultraviolet range.
It may also cause fluorescence. |
| 2. | Blue | 455 – 492 | Above 1W | It often leverages frequency doubling. |
| 3. | Green | 492 – 577 | Below 1W | It appears brightest to the naked eye.
It’s also a complicated device to set up as well. |
| 4. | Yellow | 577 – 597 | Below 10mW | Isn’t commonly used for pointers as it demands active cooling. |
| 5. | Red | 622 – 780 | Below 5mW | Typically only requires one laser diode. |
Laser Output Power
As was highlighted earlier, laser output power is arguably the variable most responsible for determining how far laser pointers can go. The output power of red, green, and blue laser pointers also has another function.
In addition to influencing the level of relative brightness a laser can put out, this factor also determines which safety class these different electromagnetic devices will fall in. This brings us to the element specification parameter: safety.
Laser Safety
The safety of this portable device has continued to receive increasing awareness over the years. The potential eye hazard and the fact that it has inhibited a number of police helicopter searches have led to governments around the world taking stringent action with laser pointers.
In the past, most laser pointers that were commercially available to the public had relatively low output power. Most of these didn’t exceed 5mW.
However, as the demand for this electromagnetic device increased, more affordable products with up to 20 times as much power began to surface.
Considering that even a split-second exposure to a 200mW green laser pointer at a 100 yards distance could cause permanent eye damage, laser pointer safety was amplified by several regulatory bodies globally.
While the United States decided to limit what consumers could get legally to 5mW maximum, the United Kingdom dropped its limit even lower.
The U.S. also introduced a laser safety classification scheme that divides laser pointers into different categories. Below is a table detailing the current laser classes and safety features.
| S/N | Laser Class | Safety Features Observed |
| 1. | Class 1 | Laser pointers in this category do not present any potential for harm when used normally.
Access to the hazardous embedded lasers may be required by Service Operation. |
| 2. | Class 1M | Laser pointers in this category do not present any potential for harm when used normally unless a collecting optic is used. |
| 3. | Class 2a | The visible beams are not intended to be viewed.
It doesn’t have the potential to induce hazard upon exposure for a set period of time (1,000 seconds maximum). |
| 4. | Class 2 | It possesses visible beams that do not pose any hazard within the aversion response time (0.25 seconds). |
| 5. | Class 2M | It possesses visible beams that do not pose any hazard within the aversion response time (0.25 seconds) unless a collecting optic is used. |
| 6. | Class 3a | It is visible only and presents the same characteristics as Class 2M lasers. However, these can’t be used with a collecting optic. |
| 7. | Class 3R | It has different limits and replaces Class 3a lasers.
It has a 5 x Class 2 limit for its visible beams. It has a 5 x Class 1 limit for its invisible beams. |
| 8. | Class 3B | Its visible and invisible beams are medium-powered.
It poses risk of retinal damage and specular eye hazard. It doesn’t pose a diffuse or scatter hazard. It doesn’t pose any skin hazard. |
| 9. | Class 4 | Its visible and invisible beams are high-powered.
It poses non-beam hazards such as toxic fumes and fire. It poses threat of retinal damage and eye hazard. It poses a diffuse and scatter hazard. |
The Best Laser Output Power for Stargazing
The best laser output power for stargazing is 5mW. Lasers with this level of output have enough power and range to ensure that your stargazing experience isn’t diminished. They typically also come with the ideal safety precautions for even amateur astronomers.
A study conducted in 2010 confirmed that even with the normal air condition and light pollution, users were still able to see and follow laser beams emitted at 5mW. This means you don’t necessarily need to invest in heavy-duty laser pointers to enjoy your astronomy-related activities.
The Best Laser Pointer Color for Astronomy
The best laser pointer color for astronomy is green. This is because the human eye is more sensitive to the color green. As our eyes can follow the path that a green laser pointer travel more efficiently, these devices can contribute to a more enjoyable stargazing experience.
It also helps that the green laser pointer is on average more affordable than other colors.
Having established that, you should know your choices aren’t expressly limited to a green pointer. A purple or blue beam laser can also help you do a fine job of exploring the night sky.
Is Observing Laser Pointer Safety Precautions Important?
Yes, observing laser pointer safety precautions is very important. The main reason for this is that many laser pointers use frequency-shifting crystals to create the color we observe. So, if they aren’t handled carefully, people could be exposed to the potentially dangerous high-power invisible laser located inside the pointer.
So, even if you have a laser light pointer you’re confident falls within the acceptable legal limits, it’s always best to observe the following practices:
- Don’t point your laser beam at any person or metal object. Outside the risk of hurting the other person, there’s a real possibility that the metal surface will reflect the laser light, exposing you to retinal damage or eye hazards.
- Don’t point the laser light directly at your eyes. Also, do not point it at anyone using binoculars or telescopes for terrestrial or stargazing activities.
- Always be conscious of where you’re using laser pointers. For example, you should avoid using your laser pointer anywhere within 2 miles of an airport as that is a legal offense.
- Don’t give your laser pointer to a child or anyone inexperienced with the gadget. As they won’t be very familiar with the best ways to use it safely, they’re in greater danger of hurting themselves with it accidentally.
- While you may use your laser pointer to ward off birds that may damage planted crops, don’t use this gadget on pets or wildlife. Laser beams pose a potential eye hazard to these animals otherwise.
Bottom Line
Back to the question, just how far can laser pointers go? With a pointer of the right color and power output, the beam can travel several miles. While this can make using the laser more entertaining, it also makes it more potentially dangerous.
Along these lines, one of the best things you can do is make sure you pick a safe and reliable laser pointer and learn how to use it with a telescope responsibly.
See more on using laser pointers for astronomy here.
