How to Safely Observe the Sun with a Telescope




How to Safely Observe the Sun with a Telescope


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The Sun has always captivated human curiosity for many years. The radiant gas-filled celestial object is at the heart of our Solar System and has a lot of features that are interesting to look at.

From its enigmatic solar flares to the ever-changing surface, the Sun has a lot to fascinate any astronomer, whether experienced or amateur stargazers.

In this article, I will take you through how to safely view the Sun with a telescope. We will discuss the safety measures you have to take before looking at the Sun, as well as what equipment to use to get the best possible images of the Sun.

Stick with me through the end to learn about this and other related topics about the sun. Let’s get started.

Facts about the Sun

One of the less-known facts is that the Sun is actually not much different from other stars in our universe. It only appears different because of its proximity to our planet Earth.

The distance between us and the Sun is about 93 million miles.

The huge ball of gas – mostly hydrogen (91%) and helium (8.9%) – was formed about 4.5 million years ago when a lot of matter condensed in the Milky Way galaxy’s Orion Spur. Other elements found in the Sun include Nitrogen, Oxygen, and carbon. 

Because of the extreme temperatures in the Sun, all of the elements found in it remain in a gas-like state called plasma. Like Earth, the Sun comprises different layers, but all of them are in a gaseous state; there are no solid regions.

There are 6 layers in total, which include the core, the radiative zone, the connective zone, the photosphere, the chromosphere, and the corona.

And then there is gravity! The gravitational field of the Sun is powerful enough to hold all planets, several asteroids and comets, meteoroids, and dwarf planets in an orbit around itself. 

As weird as it may sound, without the planet, we probably wouldn’t know life as we know it now. The universe wouldn’t be as it is now because the celestial objects that orbit around the sun would have drifted into space or might not have been formed.

The Sun has several amazing features. Its surface is ever-changing, and there are flares and sunspots that are just awe-striking. While viewing the Sun will give one of the best skywatching experiences, it demands great care.

The Importance of Safety when Viewing the Sun with a Telescope

Forget the telescope; viewing the sun directly with your naked eye is never safe. It is always advisable to put on proper eye protection when looking at the Sun, even if it is partly obscured.

The Sun’s rays have harmful Infrared and Ultraviolet rays that are capable of damaging parts of your eyes, such as the retina. The rays can also cause blindness.

You should never observe the Sun with regular sunglasses. As we will see later, you should consider investing in decent solar filters or solar eclipse glasses.

How to View the Sun with a Telescope

While you can view the sun directly with special solar eclipse glasses, you will need a telescope to get the best close-up view. However, I must mention that you don’t need a huge telescope.

Any small 2-inch telescope will do the work just fine. Larger telescopes can easily overheat since they allow a lot of sunlight down their tubes.

If you have a bigger scope, you can still use it, but be sure to limit the amount of sunlight falling into the tube. For example, if you have a 12-inch telescope, you can limit the sunlight entering the tube by cutting a 2-inch circular hole into paper or cardboard and then attaching it to the telescope’s aperture.

Also, you can buy a white light solar filter. There are so many options on Amazon, so you should find one that perfectly fits your telescope’s aperture.

White light solar filters block most (99.99%) of light from the Sun and this includes the harmful infrared and ultraviolet rays.

The filters are also designed to view different features of the sun. For instance, you can get filters that will allow you to get images of the solar photosphere or sunspots that appear as dark regions. 

There are various types of filters you can use. Mylar filters will give you a blue Sun, resulting in better contrast between the faculae and the Sun’s disc.

Glass filters produce an orange-to-yellow Sun. This is because these filters are often coated with Chromium or Nickel.

There is also another type of filter you can use called the hydrogen-alpha filter. These filters show various details on the surface of the Sun. 

They only allow light coming from hydrogen atoms to get through the telescope. I must reiterate the fact that both types of filters come in different sizes and shapes.

You must, therefore, make sure you are getting one that fits your telescope.

Must I Use a Solar Filter to Observe the Sun with a Telescope?

If you have a regular telescope, it is highly advisable to use a solar filter. It will not only protect your eyes but also give you the best possible chance of seeing various surface features of the Sun. 

Most solar filters also come with additional magnification that will help you see more detailed images. You will be able to see granulation details, and sunspots, as well as see the texture of the sun.

However, there are also telescopes specifically designed for viewing the Sun:

Dedicated White Light Solar Telescopes

Personal solar telescopes are designed to easily sustain the heat from the sun while still maintaining high resolution so the user can get detailed images of the Sun. With this telescope, you can view the Sun all day without running the risk of getting eye damage.

Most personal solar telescopes have apertures that don’t exceed 4 inches. While this may not sound like much, you will be surprised how expensive the best-dedicated models of these scopes are.

Manufacturers meticulously built these telescopes to cope with viewing the Sun for several years. They also come with various amazing features. For instance, you can adjust them to reveal specific wavelengths of sunlight.

These telescopes will give you very detailed images of the sun and its surface features. 

They do not, however, perform very well in areas with air turbulence or high humidity. You will, therefore, need to choose the best possible vantage point with the least amount of water vapor and air turbulence to get the best out of these telescopes.

While personal solar telescopes are dedicated to safe solar viewing, it is still advisable not to look through the eyepiece directly. Utilize a right-angled eyepiece.

That way, you will be looking down into the telescope and not directly at the Sun.

Dedicated Hydrogen-alpha Telescopes

This is another type of telescope specifically designed for viewing the Sun. The scope only allows light coming from the hydrogen atoms.

They are, therefore, specifically designed to view the hydrogen-alpha emissions that are produced by hydrogen in the Sun.

The hydrogen-alpha telescopes are mostly used to observe the chromosphere, which needs a narrow bandwidth filter that’s centered on the hydrogen-alpha spectral line measuring 6562.8 angstroms. This telescope will give you details of the Sun you can never see with a traditional telescope. 

The scopes come with a plethora of features. One of the most outstanding is the etalon tune.

By tuning the etalon, you can make adjustments to the bandpass of wavelengths and see various surface features and prominences on the Sun. There is also ‘blue shifting,’ which allows you to adjust the frequency, making it possible for you to see the various surface features of the Sun.

With a hydrogen-alpha telescope, you can see details such as granule markings and spikey prominences that jet into space and disappear gradually. You will also be able to see snake-like dark filaments and bright white markings known as faculae.

If you have the money, this telescope gives you the best opportunity to view the Sun in great detail.

Note that some H-alpha telescopes come with various filters that you can use to view 100% of the sun all day long.

How to Observe the Sun without a Telescope

If you do not have a telescope, don’t fret because there are other ways you can use to safely observe the sun. Here are two of them:

Observing the Sun with Eclipse Glasses

The American Astronomical Society says that eclipse glasses are among the safest ways to observe the sun if you do not have a telescope.

Most of the glasses come with solar filters. Below is the procedure for using these glasses to get the best possible images of the Sun.

  • Check the solar filters to confirm they are not scratched or damaged. If you notice any form of damage, do not use the glasses.
  • If your kids are using the eclipse glasses, be sure to supervise them and make sure they are using them appropriately.
  • If you wear glasses, put your solar eclipse glasses over them. This way, you will reduce any potential harm to your eyes and give yourself the best possible chance of getting the best images.
  • Before you look at the sun, put on the eclipse glasses. Look away from the sun any time you want to remove the solar eclipse glasses.

How to Observe the Sun with Binoculars

You can also observe the Sun with a decent pair of binoculars, and there are two ways to do this. First, you must use solar filters on the binoculars’ objective lenses and not on the eyepieces. You want to get quality solar filters specifically designed for binoculars. 

The second way is to purchase specially designed binoculars that come with built-in solar filters. With this pair of binoculars, you can easily observe the whole solar disc without any risk of eye damage.

However, one of the biggest downsides of these special binoculars is that they are not as versatile as regular ones.

Features to See when Observing the Sun with a Telescope

There are many features of the Sun you can see when observing the Sun with a telescope. 

They include the following, among others:

Prominences: These are dense, cloudy materials that appear just outside the photosphere of the Sun. The gassy cloud is held by the huge magnetic field of the Sun. The cloud of gas is hot and mostly made up of hydrogen and helium. They appear in a red glowing loop. 

You can observe prominences during the total eclipse of the Sun when the Moon blocks sunlight completely. You must use solar filters or special telescopes when observing prominences at any other time.

Filaments: These are large arcs consisting of dense and electrified gas. The arcs are also held in place by the Sun’s magnetic field. Filaments are long and dark, and this is because of the surroundings which are cooler.

They last several days to weeks. They are almost similar to prominences, only that they are seen from a different angle. They are easily observed with H-alpha scopes.

Sunspots: These are dark and cool regions that appear on the bright surface of the Sun’s photosphere. They result from the very strong magnetic activity in the Sun. Sunspots often appear in pairs, with each having opposite magnetic polarity.

Granules: These appear as small bubbles. They have a textured appearance due to the hot gas that’s continuously rising from the core.

Final Thoughts

Viewing the Sun with a telescope shouldn’t be difficult. With the right tools, such as solar filters, you are going to see some of the most outstanding surface features of the sun.

Follow the tips provided in this guide to have the best possible images of the Sun.

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