Can You Use A Telescope To Look At The Sun?

There are some interesting phenomenons where the earth’s biggest star, the sun, is the main protagonist. To say that it’s one of the things both experienced and amateur astronomers look forward to would be a massive understatement. Many of them would want to take a look at those sunspots that are starting to regroup, as well as the moon’s ominous silhouette during an eclipse.

It might seem evident, but staring at the sun doesn’t sound like something precisely safe. Time and time again, many people have advised against it, and, in all honesty, it’s not impossible to see why.

After all, it would put anyone’s eyesight into jeopardy because of how bright its disk is. A permanently damaged retina, loss of vision, and blindness are among the consequences of direct exposure. Thus, the only safe way to make some solar exploration is to filter most of the light coming from this gigantic celestial being, which translates into 99% of it.

With all this information in mind, the conclusion is that looking at the sun with an ordinary telescope won’t do good to anyone, regardless of the quality of the equipment. You can get a specialist telescope for looking at the sun and we have put together a Best Solar Telescopes guide.

However, there are other alternatives that allow both experienced and new users to take a look at any changes that might happen inside this beautiful yet ominous fellow.

One of them is getting solar observing glasses, as well as buying Arcwelder’s glass. Why? It’s simple: These artifacts reduce sunlight for safe viewing, allowing astronomers to look at it without a telescope.

Pinhole Projection

Another option is to project the sun with a technique called “pinhole projection,” by using a long box with a pinhole that will project the sunlight into a viewing card.

Of course, what does this have to do with a telescope? Well, it can be used to have a better image of the sun, something smaller models can accomplish with ease by crafting a small, cardboard shade collar, placing it around the equipment, below the area where the lens is usually at.

Then, the observer would put a paper behind it, to serve as a projecting surface, preferably across the room.

The people at Sky and Telescope stress that one should only look at the spot of light that falls on the paper, mainly because staring directly through the hole can do irreparable damage to the astronomer’s eyesight.

While it’s true that it has been mentioned already, it is crucial to emphasize how dangerous this is, so proceed with caution. On the other hand, in case that they only wish to look at it through a telescope, using a sheet of solar-filter material, strictly made for these purposes, can be considered an alternative as well.

This one is considered as the most accessible and most affordable option, pinhole projection aside.

Telescope Sun Filters

How to use the filter? Simple: By making sure to place it at the front of the telescope, covering the entire opening. For bigger models, one can create a mask with a hole that reaches the 3 or 4 inches. It cannot be stressed enough how important it is to cover it entirely for it to work.

Solar filters for telescopes are mostly made of metal-coated or mylar glass. Both materials block the majority of the sunlight, often surpassing the 99% mark, preventing it from entering the tube.

There are many manufacturers in the market, but this article won’t be focusing on them.

As with many other products, whether it’s sports or astronomy gear, a regular filter has a high-end counterpart. What makes them so special? Well, they come with refractors that have apertures of around 40 to 60 millimeters.

They mostly include built-in interference filters, but there are also sets that can be attached to the front end of the refractor. Unlike their regular siblings, these tend to be the most expensive option, although their popularity is justified.

The main reason behind it is that a high-end filter allows the user to take a look at those hidden characteristics that wouldn’t be perceived with the more affordable options, such as prominences and filaments.

Keplerian Telescope

Now, if the astronomer wants to use neither pinhole projection nor filters, another way to safely look at the sun is by using a keplerian telescope.

It mostly consists of a wooden, folded-path that uses mirrors to project a solar image onto a viewing screen through a lens.

They’re less complicated than regular telescopes like the Celestron NexStar 4SE, but don’t provide the same quality of a high-end filter.