Many beginners ask me if viewing through a telescope can damage their eyes in the long run. I’ll explain exactly that in this article.
Can a telescope damage your eyes? No, a telescope won’t damage your eyes unless you are doing something that you shouldn’t, like aiming your telescope directly towards the sun and trying to observe it.
There are specific rules that you need to follow for safe stargazing. If you don’t follow these, then there are high chances that your eyes might get damaged.
Also, you must use a telescope that follows industry-standard safety protocols. Most decent telescopes in the market do that. If you want my recommendations, please check out my guide on the best telescopes for viewing planets and galaxies.
Now, let’s see what those rules are.
You Must Not Look At The Sun Through A Telescope
Let me share an incident with you.
In 2016, TV presenter and well-known astronomer Mark Thompson decided to do something interesting. He thought of not only explaining but showing the severe consequences of looking at the sun through a telescope without any filter.
Mark used a dead pig’s eye and a telescope with 50x magnification. He placed the eye at the eyepiece of the telescope. Unfortunately, there was no filter to protect the eye. At first, everything seemed normal. However, just after 20 seconds, smoke started to come out of the eye.
When looked closely, it seemed that the light burned through the eye. So mark decided to dissect the eye to find out whether the retina was intact. Sadly, the retina was burned too.
This little experiment shows how dangerous looking directly at the sun through a telescope can be.
Do you know why this is extremely dangerous? Let me explain.
We all know that magnifying glass focuses the sunrays into a single point. At that point, the temperature increases so much that even a piece of paper can catch fire. The same thing happens with the telescope.
With direct sunlight falling onto the telescope, it works like a magnifying glass and can cause severe damage to the eye. That being said, it is also foolish to look directly at the sun without a telescope. Just don’t do that.
Mark chose the pig eye for this experiment because pigs share the most biological resemblance with human bodies. However, in this case, the damage won’t be as bad as the pig eye. Indeed, you won’t keep looking at the sun for 20 straight seconds.
In the case of the human eye, the damage will be a little bit different.
First of all, like the pig eye, there won’t be any retina burning. However, there will be photochemical changes occurring in your eyes. This change can seriously affect your vision, and it can take up to 1 year for your vision to return to its normal state.
If, for some reason, you need to look at the sun through a telescope, be sure that you have all the protective gears with your, mainly the filter, to reduce the impact of the sun’s rays.
Is It Safe To Look At A Full Moon?
Yes, it is. The light reflected from the moon’s surface has an intensity level very, very small compared to that of the sun. So, there is no chance of damaging your eyes by looking at a full moon.
However, the brightness of the full moon through a reasonably powered telescope can certainly make your eyes feel dazzled. In such cases, we use neutral density moon filters to reduce brightness slightly.
Is It Safe To Look At The Blood Moon?
Yes, it is. No need to worry. Although, for any reason, if your eyes start to feel uncomfortable, use a moon filter to tone down the brightness.
Is It Safe To Look At A Lunar Eclipse?
Yes, lunar eclipses are safe to watch through a telescope or naked eyes. However, solar eclipses are not. They can significantly damage your eyes, especially if you look at the solar eclipse through a telescope.
So, I hope by now you’ve got your answer. Telescope won’t damage your eyes, provided you follow all these basic rules up to the T.