The Ultimate Guide to Observing the Sun

“Here comes the Sun, and I say, ‘It’s all right.’” Do these catchy lyrics sound familiar? This classic Beatles tune is a standout for many listeners with its hopeful lyrics, representing new life and new beginnings. Each morning, we count on the Sun to rise in the east and greet us with its bright rays to begin a new day. Whether it’s in full view or hidden behind clouds, the Sun is always there, providing light, warmth, and energy that is essential for life on Earth.

The Sun, at times referred by its Latin name, Sol, has been a focal point in culture, folklore, and religion since archaic times. Some ancient Egyptians practiced a monotheistic religion centered on Ra, the Egyptian Sun God. In the Aztec religion, human sacrifices were demanded by the Sun Gods Huitzilopochtli and Tezcatlipoca. Hawaiians have their legend of Maui, whose mother, Hina, was unable to finish drying her clothes. As the story goes, Maui wove a magical lasso and climbed to the top of Haleakala to snare one of the Sun’s rays. After a long, tiring battle, the Sun finally conceded to Maui and promised to slow down and give the people more hours of sunlight to finish their chores.

Without a doubt, the Sun is crucial to our planet Earth. We need its heat and light for life to exist. It affects the weather, food production, the growth oxygen producing trees, and so on. Similarly, the Sun influences the environments on all the other objects in the Solar System.

So, whether you’re a “Sun worshipper” or just curious to learn more about our nearest star, this guide will familiarize you with the Sun and offer some important tips on how to safely observe our giver of life and energy!

 

What is the Sun?

The Sun is a star at the center of our Solar System. Our Sun really isn’t much different from other stars in the night sky, but it seems different because of how much closer it is to us.

This huge, luminous ball is composed of burning gases—primarily hydrogen (91%), helium (8.9%), and a small percentage of heavier elements such as carbon, nitrogen, and oxygen. Due to the Sun’s extreme temperatures, these elements stay in a gas-like phase called plasma. This gaseous ball formed about 4.6 billion years ago when matter condensed in an arm of the Milky Way galaxy called the Orion Spur.

The Sun is classified as a main-sequence star or a yellow dwarf star that produces heat and energy. Just as the Earth’s structure consists of different layers, the Sun is also made of layers, but they are entirely gaseous with no solid regions. The six layers from outwards to inwards include: the corona, chromosphere, photosphere, convective zone, radiative zone, and the core.

The Sun’s gravitational field is so powerful that it can hold all eight planets, the dwarf planets, countless asteroids, comets, and meteoroids in orbit around itself. If the Sun didn’t exist, these objects would have drifted off into space, or might not have ever formed in the first place.

 

How to Safely Observe the Sun

The Sun is an amazing ball of hot swirling gases; its scintillating surface can be very interesting to observe. However, there are many inherent risks involved with solar observing that everyone needs to be aware of. The Sun’s ultraviolet and infrared rays can damage your eye’s retina, leading to loss of vision and permanent blindness!

If you are thinking of observing the Sun, your first concern should always be protecting your eyes. But as long as you carefully follow all the rules and guidelines below, solar viewing is safe—not to mention a fun and rewarding part of your astronomy hobby.

Most importantly, you’ll need to use an ISO 12312-2 certified safe solar filter that filters out more than 99.999% of intense visible light from reaching your eyes.

 

WARNINGS, RULES, AND GUIDELINES FOR SAFE SOLAR OBSERVING

  • Never look directly at the Sun with the naked eye or with any optics without proper solar safe filters. Permanent and irreversible eye damage may result.
  • Never use your optics to project an image of the Sun onto any surface. Internal heat build-up can damage the optics and any accessories attached to it.
  • Never leave your optics unsupervised. Make sure an adult who is familiar with the correct operating procedures is with your optics at all times, especially when children are present.
  • Never take a risk by using uncertified solar filters. Solar products must conform to and meet the transmission requirements of ISO 12312-2, Filters for Direct Observation of the Sun. EN 1836:2005 + A1:2007 (E) for an E15 Filter for the Direct Observation of the Sun and, AS/NZS 1338.1:2012, Filters for Eye Protectors.
  • Always check your solar filters for any damage or tiny holes before using it. Throw away the filter if any damage is detected.
  • Do not use unsafe filters. Some examples include black-and-white and color negatives, exposed film, X-rays, smoked glass, neutral density filters, and polarizing filters. Stacking multiple pairs of sunglasses is also unsafe, no matter how dark the glasses are. Most of the items listed above transmit high levels of infrared radiation that can cause a thermal retinal burn and permanently damage your vision.
  • If using a solar filter on your telescope, make sure you use a certified filter that covers the telescope’s entire front aperture. Always remove your telescope’s finderscope or make sure its lens caps are secured or else concentrated sunlight will burn out the crosshairs and could even burn your skin if you are within range of the eyepiece!
  • Never use a solar filter that screws into the bottom of your telescope’s eyepiece. The glass in the filter could crack from severe heat buildup, causing permanent damage to your eye.
  • Never look directly at the Sun—even if it is low on the horizon—without proper eye protection. Your vision could still be damaged, even if you don’t feel any discomfort because there are no pain receptors in the eye. You can be damaging your eye and not know it until you start having blind spots in your vision.
  • Never use a solar filter that is designed to be looked through (such as solar glasses) with your telescope. Never place this type of solar filter directly over your telescope’s or binocular’s eyepiece(s) to observe the Sun. The intense heat can burn right through your solar glasses.

For more information on solar safety, check out this video:


For other important solar safety videos, click here.

 

There are several ways you can observe the Sun both indirectly and directly with full confidence that your eyes will be fully protected from the harmful rays of the Sun.  

Pinhole Projection

Time tested and proven safe, this is a great indirect method for observing the Sun, especially during solar eclipses. Simply take two pieces of carboard or paper plates and punch a tiny hole in one of them to allow sunlight to pass through onto the other card. The further you separate the cards from each other, the larger the image scale will be, but the solar image will be dimmer.

Interlacing Fingers

No additional equipment is required for this indirect viewing method. Just interlace your fingers, leaving small gaps between them. Standing with your back towards the Sun and allow the sunlight to pass through your fingers and onto the ground. During the partial phases of a solar eclipse, you will be able to see tiny crescents being projected.

Tree Leaves

Yet another indirect method to view partial phase of a solar eclipse is allow nature to play a role. Sunlight filtering through tree leaves will leave countless crescent Sun images on the ground or a wall. During an annular eclipse during maximum coverage, you will see many circle-like shadows with bright rings. It truly is a sight to see!

TV/Internet

The safest way to watch a solar event such as a solar eclipse is to view the event on your TV or computer in the comfort of your own home or office. Many news outlets will broadcast the event safely for all to see—and probably in much higher resolution with expert commentary.

Arc Welder’s Glass

Moving into direct methods of solar viewing, one of the most widely available filters for safe solar viewing is shade number 14 welder's glass (darkest grade), which can be obtained from any welding supply outlet (source: NASA Eclipse Website). Please note that the Sun’s image through the #14 welder’s glass will appear green.

White Light Solar Filters

A white light solar filter which works in the visible spectrum, is an ideal way to turn a nighttime astronomical telescope into a daytime solar observing telescope. It is designed to view the solar photosphere and sunspots. Solar filters can be metal on glass (most durable and costly), aluminized polyester film (also known as aluminized Mylar), and polymer. Filters can be easily attached to the front cell of different types of optical telescopes and come in all different sizes that lock into place or are snug fitted. Celestron’s EclipSmart 60 and 70mm refractor solar filters have set screws in the side of the filter housing to grab onto the lens shade for a secure fit, while the 6” SCT and 8” SCT and EdgeHD solar filters are snug fitted but also come with Velcro straps for added security. Each EclipSmart solar filter provides a more natural orange solar disk view and feature scratch resistant polymer produced by American Paper Optics. They feature Solar Safe filter technology, the ultimate protection from harmful solar radiation, including both IR and UV light, and filter 99.999% of visible light.

Solar Eclipse Glasses

Solar eclipse glasses such as Celestron’s EclipSmart Solar Safe Shades, are easy to wear and feature Solar Safe filter technology for the ultimate protection from harmful solar radiation, including both IR and UV light, and 99.999% of visible light. They provide a more natural orange solar disk view and are perfect for solar viewing anytime or viewing a solar event such as the partial phase during a solar eclipse. Solar glasses should never be used as solar filters for a telescope.

Solar Safe Binoculars

Celestron’s EclipSmart 10x25 mm Solar Binocular is small, compact, and easy to transport in a jacket pocket while traveling to a solar eclipse viewing location. It’s an ideal white-light solar viewing binocular that provides a full magnified view of the entire solar disk. It features Solar Safe filter technology for the ultimate protection from harmful solar radiation, including both IR and UV light, and 99.999% of visible light.

Dedicated White-Light Solar Telescope

Celestron’s EclipSmart Travel Solar Scope 50 is a dedicated white-light solar scope for the observer on the go. It’s lightweight, compact, and easy to transport while traveling to a solar viewing event. It is an ideal solar telescope to view the solar photosphere and sunspots. The 50mm refracting solar scope uses Celestron’s Solar Safe, ISO compliant, full-aperture glass filter material to ensure the safest view of any solar event. This solar scope offers much higher magnifications for viewing sunspots or planetary transits than you would otherwise get using solar eclipse glasses or binoculars.

Dedicated H-alpha Solar Telescope

A unique and exciting way of observing the Sun is through a telescope that is designed to observe the H-alpha emission produced by hydrogen. Observing the chromosphere requires a very narrow bandwidth filter centered on the H-Alpha spectral line of 6562.8 angstroms. The views through an H-alpha telescope make the Sun come alive with incredible detail not seen in a telescope using a traditional white light solar filter. By “tuning” the scope’s etalon, fine adjustments can be made to the bandpass of appropriate wavelengths to see prominences and surface detail since the frequency can be shifted due to “blue shifting”. Granule markings can be seen on the Sun’s surface while spikey prominences can appear to jet out into space and then disappear over time. Dark filaments can appear like snakes while bright, whitish markings called faculae can also be seen prior to sunspot appearances. You can find several third-party H-alpha telescope manufacturers that offer these specialized solar telescopes, but they can be quite expensive.

See the full line up of Celestron EclipSmart Products 


EclipSmart solar products feature Solar Safe filter technology providing the ultimate protection from harmful solar radiation, including both IR and UV light, and 99.999% of visible light.  Celestron Solar Safe filter technology is GUARANTEED SAFE for direct solar observation and has been independently tested by SAI Global Assurance Services.  Solar Safe products conform to and meet the transmission requirements of ISO 12312-2, Filters for Direct Observation of the Sun, EN 1836:2005 + A1:2007 (E) for an E15 Filter for the Direct Observation of the Sun and, AS/NZS 1338.1:2012, Filters for Eye Protectors.

 

 

Solar Observing Targets

Sunspots

Sunspots are cooler and darker regions that appear on the Sun’s bright surface called the photosphere.  They are caused by strong magnetic activity inside the Sun and appear in pairs with opposite magnetic polarity. Most and have a central dark umbra and a lighter shaded penumbra. Sunspots are on the move as they can be seen slowly making their way across the Sun’s surface and changing in size. Some sunspots are large enough to be seen without any magnification through safe solar glasses. Using a white light solar filter with a telescope will reveal great detail. Sunspots follow a solar cycle of eleven years.

Granules

Granules appear like small bubbles you would see rising to the top in a kettle of boiling water. They are small (approximately 900 miles in diameter), and their textured appearance is the result of hot gas continuously rising up from the Sun’s core. Granules are the tops of convection cells that spread out across the solar surface, cool, then sink back down. They last about five to ten minutes and are best seen using high power in good seeing conditions. They are superb to view in an H-alpha solar telescope.

Limb darkening

When the edge of the Sun’s disk appears darker than in its center, this is called limb darkening. While using a telescope with a white-light solar filter to view the Sun’s disk, you will be peering right into hotter layer of the Sun’s photosphere. The hotter the gas, the brighter it will appear. However, the view at the edge (limb), is looking towards the outer layers of the photosphere where gas is cooler and therefore appears darker. Experts say this is proof that the Sun has an atmosphere. Limb darkening is more noticeable in astroimages, but when you’re looking for it visually, it’s unmistakable.
Faculae

Faculae are large bright areas in the Sun's photosphere caused by magnetic activity. They are much hotter than the surrounding photosphere. Often seen near the darker limb of the Sun’s disk, faculae make the Sun appear brighter and are a sign that sunspots will soon follow. Monitor the Sun’s eastern limb for any faculae rotating into view. Use a white-light solar filter and high power.

Prominences

One of the most dramatic solar phenomena to observe through an H-alpha telescope or with your eyes during the totality phase of a solar eclipse are solar prominences. They are towering structures of hot gases of electrically charged hydrogen and helium, often in the shape of glowing red loops. Prominences are expelled hundreds of thousands of miles into space and into the solar corona—where they can reside for several weeks or months. They form in about a day and are anchored in the photosphere. You can safely observe prominences with the naked eye only during totality, when the Moon completely blocks the Sun’s extremely bright photosphere. Eye protection must be used as soon as totality is over. However, with an H-alpha telescope, you can view solar prominences any time they erupt, thanks to the scope’s specialized hydrogen narrow bandwidth filter.

 Filaments

Solar filaments are large arcs of very dense electrified gas held in place by powerful magnetic fields. They’re usually found above sunspots. Filaments appear long and dark because of their cooler surroundings and can last for several days or even a few months. Filaments are actually the same as prominences, just viewed from a different angle. Like prominences, filaments are easy to spot in an H-alpha telescope.

 

 

Sun Facts

  • The Sun is approximately 4.603 billion years old. Astronomers believe it’s about halfway through its lifespan.
  • It’s the largest object in our Solar System, comprising 99.8% of the system’s mass.
  • The Sun is composed of 91% hydrogen, 8.9% helium, and smaller amounts of oxygen, carbon, iron, neon, and other elements.
  • The Sun is in the center of our Solar System with Earth orbiting 93.603 million miles away—a distance also known as 1 AU (astronomical unit).
  • Sol is a medium size star classified as a yellow dwarf. There are many stars in the Universe that are larger and smaller than our Sun.
  • The Sun's magnetic field spreads throughout the Solar System by the solar wind.
  • The Sun’s hot plasma take the shape of a near perfect sphere with a diameter of 865,370 miles.
  • It takes eight minutes for light to travel from the Sun to the Earth. This distance is the basis for establishing the speed of light.
  • The Earth and Sun’s interactions result in seasons, ocean currents, climate, and the auroras (northern/southern lights).
  • 3 million Earths would fill the Sun’s interior if it were hollow.
  • The solar surface temperature is 10,000 degrees Fahrenheit. Temperatures can reach more than 27 million degrees Fahrenheit within the core.
  • Inside the Sun, hydrogen atoms, under high pressure from gravity, go through a process called nuclear fusion and are converted into helium atoms. This process generates an immense amount of heat, causing radiation and sunlight to reach the Earth.
  • A Coronal Mass Ejection (CME) is an explosive outburst of billions of tons of super-heated plasma from the Sun. When CMEs hit the Earth, our atmosphere usually protects us, and the Earth’s magnetic field deflects the electrified plasma to the north and south poles where they light up the night sky as auroras. If a CME penetrates the magnetosphere, it has the potential to wreak havoc on the power grid, satellites, electrical and communications equipment and more!
  • The Sun is labeled as a G-type main-sequence star or G2V.
  • There are billions of stars in the Milky Way Galaxy, but the Sun is the most important star and energy source for Earth and its inhabitants.
  • Like all the planets, the Sun rotates on its axis. One solar day lasts about 27 Earth days. It spins fastest at its equator, where it takes about 24 days to rotate. The poles take more than 30 days.
  • The Sun’s gravitational force is so strong that it can hold all eight planets, many dwarf planets, at least 170 moons, and countless comets, asteroids, and meteors in its orbit.
  • The Sun emits different forms of electromagnetic radiation: visible light, infrared, and ultraviolet rays, which make up 99% of these radiations.
  • When it uses up its supply hydrogen and helium and nears the end of its lifespan, the Sun will expand and swallow up the inner planets. It will then collapse and become a white dwarf.
  • Sunlight consists of all the colors mixed together but appears white to our eyes.
  • From the Northern Hemisphere, Earth is farthest from the Sun in July and is closest to the Sun in January!

 

Special Solar-related Phenomena to Explore

Observers starting out in amateur astronomy may limit themselves to nighttime objects like the Moon, planets, bright star clusters, and nebulae as celestial observing targets. But did you know that the Sun is also responsible for many solar-related phenomena that can be enjoyed during the daytime, right from your own backyard? Of course, remember to follow the solar observing rules above and protect your eyes at all times.  

Eclipses

A solar eclipse can only take place when the Moon is new and comes between the Sun and Earth, casting its shadow (umbra) on Earth. However, a solar eclipse does not take place each new Moon because the Moon’s orbit is tilted relative to Earth’s orbit. Therefore, the Moon’s shadow often passes above or below Earth. There are three types of solar eclipses: total, annular (ring of fire), and partial. Please note the only time it is safe to observe a solar eclipse with your unaided eyes is during totality. Under no circumstances should you ever observe a solar eclipse–annular or partial phases without safe solar glasses. The next annular eclipse visible in the US will take place on October 14, 2023. The next total solar eclipse visible in the US will take place six months later on April 8, 2024. The two paths will cross through the state of Texas.

A lunar eclipse can only take place during a Full Moon when the Earth is between the Sun and Moon, and the Moon moves into the Earth’s shadow. Anyone located on the night side of Earth will be able to witness the eclipse, and it will be completely safe to do so. No eye protection is required. There are three types of lunar eclipses: total, partial, and penumbral. Unlike a total solar eclipse where totality only lasts several minutes, the length of totality during a total lunar eclipse can last longer than 90 minutes. The Earth also casts a lighter shadow called the penumbra. If it touches the Moon, any darkening will most likely be seen if the Moon is closer to the umbra shadow zone. In most penumbral eclipses, the shadow is quite subtle that most people will hardly notice that a lunar eclipse is occurring. Now, if we were an astronaut standing on the Moon’s surface during a total lunar eclipse (as seen from Earth), the Sun would be totally eclipsed by the Earth! The next total lunar eclipse visible in the US will take place on May 26, 2021 and favors mainland western US, Alaska, and Hawaii.

Solar Transits

A solar transit occurs when any object passes between the Sun and the Earth and appears as a black disk moving across the face of the Sun–including the International Space Station! The two inner planets Mercury and Venus are well known for transiting the Sun, a process that can take several hours. Mercury last transited the Sun on May 7, 2003; November 8, 2006; May 9, 2016; and November 11, 2019. The next transit will occur on November 13, 2032. Venus transits are much rarer and occur in a pattern that repeats every 243 years. The last transit of Venus took place on June 5-6, 2012 and was the last Venus transit of the 21st century. The next Venus transit will take place on December 10-11, 2117 and December 8, 2125.

Green Flash

The elusive green flash is a meteorological optical phenomenon that sometimes occurs during sunrise or sunset when optical conditions are just right. Some eagle-eyed photographers may see the distinct green “flash” of light visible just above the upper rim of the Sun's disk that lasts about two seconds. Patience and good luck are required to spot the green flash. It is never recommended to stare directly at the Sun, even when the Sun sets, without proper eye protection.

Rainbows

Of all the sky phenomena, rainbows are the most well-known. Seen often after a rainstorm, rainbows are produced as sunlight strikes water droplets in the air that act like prisms, dispersing the light and separating the colors. Rainbows take the form of a circular arc and only occur opposite of the Sun. The lower the Sun is towards the horizon, the higher a rainbow can be seen in the sky. Rainbows are actually full circles and can be seen in their full form from the air if conditions are right. But for ground observers, the horizon will limit the view. Primary rainbows are always seen with red on the outer band with violet on the inner band. At times, a secondary or double rainbow may appear due to light being reflected twice inside water droplets. In this case, a secondary arc can be seen on the outside of the primary rainbow’s arc. The colors will be reversed with violet on the outer band and red on the inner band.

 Sun Dog

A sun dog is a concentrated spot of sunlight about 22 degrees to the left or right of the Sun. Sun dogs usually form in pairs on either side of the Sun–usually when it’s lower in the sky. They can occur when sunlight refracts through icy cirrus clouds containing hexagonal plates during cold weather. These crystals act as prisms that bend light rays passing through them. As the crystals sink through the air, they become vertically aligned and refract sunlight horizontally to create the appearance of sun dogs, also known as phantom Suns. They can be colorful like a rainbow; however, rainbows are seen looking away from the Sun while sun dogs are seen looking towards the Sun.

Solar Halo

A solar halo appears as a white circle that forms a ring around the Sun. You can see them at any time of the year. The halo, similar to a lunar halo, is created when sunlight passes through ice crystals within high altitude cirrus clouds. It has a radius of 22 degrees. Unlike sun dogs, which appear on both sides of the Sun when it’s lower in the sky, a solar halo can be visible when the Sun is higher or lower in the sky.

Sun Pillar

A sun pillar appears as a beam of light that forms when sunlight reflects off the surfaces of ice crystals associated with thin, high-level clouds such as cirrostratus clouds. It can reach five to ten degrees high while the Sun is low in the western sky prior to sunset, or low in the eastern sky just after dawn. Sun pillars can even be seen while the Sun is below the horizon.

Aurora

Named after the Roman goddess of the dawn, the Aurora Borealis is the northern lights in the Northern Hemisphere, while the Aurora Australis is the southern lights in the Southern Hemisphere. Auroras usually appear green or white, but can also exhibit colors like blue, red, and even pink. Auroras can dance, change shape, appear as dim as thin clouds or be bright enough to light up the landscape. Auroras form when the Sun’s solar wind is ejected out into space and directly in Earth’s path. The Earth has a magnetic field called the magnetosphere that deflects most of the solar particles, but some make it through, evoking oxygen and nitrogen atoms that light up, producing a spectacular and colorful light show near locations by the poles.

Glory

Look out the window the next time you’re on an airplane to spot this neat effect. Look for the plane’s shadow projected onto clouds and surrounded by a multi-colored circle of lights. This circle is called the glory. It is always located opposite from the Sun and is caused by the deflection of sunlight hitting tiny water droplets in the clouds.

Zodiacal Light

The zodiacal light is a diffuse, triangular, whitish glow that can be seen at the sunrise or sunset points on the horizon before dawn breaks or after twilight ends. It can extend from the horizon along the zodiac and straddle the ecliptic. The zodiacal light is caused by sunlight scattered by interplanetary dust. Your best chance of seeing this rare occurrence is during twilight after dusk in spring and before dawn in fall when the zodiac is at a steep angle to the horizon. Because the zodiacal light can be faint, moonlight or city lights can make it difficult to spot.

 

 

Helpful Observing Hints

Tip #1: Use an Astronomy App - The most modern and informative tools today can be found in astronomy apps such as Celestron’s SkyPortal mobile app. This full featured planetarium app is included with the purchase of any Celestron telescope, available from the Apple App Store or Google Play. SkyPortal instantly provides new telescope owners with a wealth of information at their fingertips, including audio and written descriptions about various objects, including the Sun. It also provides its celestial coordinates, a real-time sky map, rise and set times, physical and orbital parameters.

Tip #2: Seeing Conditions - Steady seeing conditions are critical while observing objects such as the Sun, Moon, planets, or double stars, although deep sky objects such as nebulae and galaxies are less affected by poor seeing conditions. Avoid times of bad seeing when our atmosphere is turbulent, and your targets appear like shimmering blobs in your telescope’s eyepiece. Start with low magnification and work your way up if the views remain steady. During good seeing, you will be amazed how sharp and detailed solar features can appear.

Tip #3: Telescope Acclimation - Set up your telescope outside and let it acclimate to the outside temperature before solar observing to avoid any distorted views.

Tip #4: Collimation - Collimate, collimate, collimate! If you own a Newtonian or Schmidt-Cassegrain telescope, make sure your telescope’s optics are collimated. It can make a difference when it comes to discerning fine solar detail. If the optics are slightly out of alignment, you may be cheating yourself out of seeing the clearest and sharpest images.

 

 

Final Thoughts

We are very fortunate to live in a world with both the Sun and Moon to light up the sky. Life could not exist on Earth if it weren’t for our Sun. The connection between the Sun and the Earth drives the seasons, weather, climate, currents, and so much more. Although there are billions of stars in the Milky Way galaxy, our Sun is special, and it belongs to all of us. Yes, there may be many other stars like it, but this Sun is ours. Extra caution should always be taken when viewing the Sun–especially if young children are present. With proper safe and approved solar filters in place, the Sun can provide us with a lifetime of viewing enjoyment. Just don’t forget to wear your hat and bring plenty of sunscreen!

To browse Celestron solar products, telescopes, binoculars, and accessories, check out Celestron.com/EclipSmart

Clear skies!