What are the Lasers on Telescopes For – Everything You Need to Know

what are the lasers on telescopes for

If you’re a pro or amateur astronomer, you’ve probably noticed that laser light is becoming a more prominent feature in many modern telescopes. How exactly does this resource fit into ground-based telescopes? What are the lasers on telescopes for exactly?

Telescope lasers have become widely accepted in astronomy. Major institutions like the Gemini Observatory North in Mauna Kea, the W.M. Keck Observatory, and the Paranal Observatory of The European Southern Observatory leverage laser systems extensively.

Exploring the increasingly prominent role of laser technology in astronomy won’t only offer more insight into your beloved hobby but it can help you feel even closer to the real stars.

To help you along this path, we’ll be taking an in-depth look at the roles that laser beams play that make them so important to optical telescopes today.

What are Lasers?

Lasers are devices that significantly increase the intensity of light and produce a highly directional ray or beam of light. In addition to light intensity amplification, lasers also generate light through the stimulated emission of radiation.

The word “laser” is an acronym that represents Light Amplification by Stimulated Emission of Radiation. However, some lasers today do not follow the principle of stimulated emission of radiation to operate.

What are the Lasers on Telescopes for?

what are the lasers on telescopes for

The lasers on telescopes are used to minimize the impact of atmospheric distortion during stargazing. The beam of light that these devices shoot optimizes adaptive optics systems and enhances image quality as a result.

The laser light used in 80-telescope observatories does much more than eliminate optical distortion and enhance the adaptive optics technology of the telescope.

Lasers also play a great role in the Gemini North Adaptive Optics facility. The GNAO Laser light is constantly upgraded to increase its features and functionalities as well. A new laser guide star facility was even founded in 2021 to help push this innovation further.

In simpler optical telescopes like reflectors, high-power laser applications prove very useful as they help you observe sharp images when viewing a light path or star in outer space.

The main reason for this is that, unlike refractor telescopes that have a simple two-lens design and rarely feature an adjustment adaptor, reflector telescopes use heavy, suspended mirrors that tend to fall out of alignment very easily.

Laser technology has come so far that when even a simple laser pointer or laser pen is used with a traditional telescope to view distant objects, you get better results from the focal lengths of the scope. The resulting image is very vivid and free of light pollution.

One of the best things about using a green laser beam is that you’ll be able to trace where your telescope is pointing, even before you look through your finderscope!

So, as long as you have a clean telescope lens, a laser pointer can help you have a more enjoyable time viewing the night sky alone or with star parties.

Why are Green Laser Pointers so Popular with Telescopes?

Green Laser Light

Green laser pointers are popular with telescopes because the human eye can pick out green light from the color spectrum more easily. As it isn’t difficult to trace the light path of a green beam, they’ve quickly become the laser light of choice for many astronomers.

Also, these lasers give off especially bright lights which come in handy when you’re gazing into the night in search of a particular celestial object. Additionally, 5-mW green laser pointers appear to consume far less power when doing this compared to laser lights of other colors.

However, you don’t have to rely exclusively on a 5-mW green laser pointer.

While a green laser beam is indeed very easy to track, there is a colorful catalog of laser lights you can use that’ll help you get sharper images as well, even if you’re not using a very powerful telescope. At the top of this list is yellow, blue, and red.

Is Laser Brightness and Power Output Very Important?

Yes, laser brightness and power output are very important. The output power and brightness of your laser pointer directly affect what you can do with the device. Also, the output power of the laser is what determines how bright it shines in the case of monochromatic lasers.

What this means is that, when two laser pointers have the same power output but different colors, the brightness of the beam of light that one device emits will likely be lower or higher than that of the other.

As an example, red lasers with a 5-mW power output have a lower brightness level compared to green lasers with the same output level.

Another important factor to consider here is that a higher power output laser doesn’t automatically guarantee you a better user experience. If you want a pointer for the image lenses of a standard telescope for backyard astronomy, you don’t need to invest in a high-end laser.

Why Getting a High-Power Laser Isn’t Always Better

Getting a high-power laser isn’t always better because it can be financially demanding and can also put your health and safety at risk. Additionally, you’ll have to refocus these types of lasers every time you use them.

Here’s more in detail:

High Cost

Added to the cost of getting a telescope, a high-power laser can make backyard astronomy more expensive than it needs to be. The main reason for the high cost of these devices is that high-powered lasers are more complex and often require more components to function.

However, unless you have more than just looking at a bright star or the International Space Station in mind, you likely don’t need high-power laser applications.

Risks to Health and Safety

Lasers in astronomy work best when they emit enough light that you can see celestial objects clearly without straining or damaging your vision. While this might be relatively easy to accomplish with regular laser pointers, that’s not always the case with high-powered lasers.

What’s more, the higher the power of the expensive laser, the more you’re at risk of eye injury when using these artificial stars.

So, be sure to keep this in mind before making a purchasing decision.

Adjustment Requirements

More expensive telescope lasers also come with the need for users to adjust them with each use. Not only can this eventually become an inconvenience but the adjustment process itself may strain and upset your night vision, even when done with care.

What is the Best Way for an Amateur Astronomer to Use a Laser Pen?

Diagonal star, eyepiece, okuler lens, barlow lens, and finderscope. Telescope parts on wooden table. Astronomy lesson exploring parts of telescope.

The best way for an amateur astronomer to use a laser pen is either to complement your finderscope or simply as a pointer. In either case, even beginner users will be able to make the most of their green laser points effortlessly.

Using Your Laser Pen with a Finderscope

Using your laser pen or pointer alongside your finderscope can help you improve your night vision exponentially. Your telescope tube will typically come with a finderscope holder. You can fit your laser pointer into that space and get the benefit of using these two tools to see better.

Not only will doing this help you cut cleanly through the layer of sodium atoms that contribute to atmospheric distortion but it can also significantly increase the speed and accuracy with which you perform this exercise.

However, some astronomers choose to completely replace their finderscope with a laser pointer. Because a laser doesn’t require you to constantly bend every time you want to zero in on distant objects, it’s slightly more comfortable to use than a finderscope.

This is more so the case if the stargazer sets their scope at a height that compels them to stoop for long periods at a stretch. A laser pointer will reduce the chances of developing back pain from this exercise without sacrificing visual quality.

Using the Laser Pointer Directly

Using your laser pointer just as it is can also be quite effective. It’s also efficient as it makes pointing very easy. This is one of the reasons that laser pens are commonly used this way at star parties. However, there’s one thing to consider if you plan to follow this approach.

For safety reasons, it’s often better to get a laser that you have to press before it shoots a beam, not one that stays on constantly. Getting a laser that’s always on may end up distracting not just you but other people around as well. Its battery will also drain faster.

Familiarizing yourself with the U.S. Food and Drug Administration’s guidelines on laser use may prove helpful as well.


So, what are the lasers on telescopes for?

Simply put, these resources help adaptive optics systems work even better. For people just entering the world of astronomy, they can make the exploration of the night sky more rewarding. The most important thing is to be sure to use the laser pointers safely and responsibly.

See more on lasers and telescopes here.


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