What is the Sun?

The Sun is a star; a large ball of gas which is undergoing the process of nuclear fusion. This process takes place in the core of the Sun and is how it creates energy, and emits heat and light out into the solar system. The Sun is actually a rather average star compared with the rest of the stars in our galaxy. The only reason it is so important to us and appears so different from all the others in the sky is because it is so close to us here on Earth. The sun is the brightest object in our solar system, and also the largest (over a million times as large as the Earth). Being the most massive object in the solar system it is also the center around which all of the other bodies in solar system orbit around including all the planets, moons, asteroids, and comets.

Facts about the Sun

Distance from Earth: 1.496×10⁸ km
Mass: 1.989 x 10³⁰ kg: (333,000 times the Earth)
Diameter: 1.392×10⁶ km (109 times the Earth)
Apparent Magnitude: -26.74
Average Surface Temperature: 5780 K
Average Core Temperature: 1.57×10⁷ K

Observing the Sun

The Sun is one of those astronomical objects that once observed more closely can change the way you think about it and its appearance in the sky. Instead of simply being that bright spot in the sky that is to intense to be looked at, it becomes a mystifying fiery orb that is constantly heating and illuminating our world, and its true power and proximity become appreciated. Many people, however, fail to think of the Sun when they think of observable objects, despite it being the single brightest object in our sky, simply because it is around during the day instead of the nighttime.

The Sun is actually a great source of enjoyment for observers, but the right precautions must be taken to ensure that no damage to one’s eyesight occurs. Even looking at the Sun with the naked eye can cause permanent sight damage, and attempting to view it with binoculars or a telescope in traditional fashion is not safe as this practice can cause blindness almost immediately. Fortunately there are several safe ways to view the Sun and allow one to see its highly active surface. (More can be read about these methods below.)

When viewing the Sun you are likely to notice one of its more interesting phenomena, the sun spots on its surface. These dark patches are sections that are cooler than most of the Sun’s surface. They are caused magnetic activity at these locations preventing heat transfer through convection. Sunspots are a dynamic phenomena, appearing and disappearing lasting from hours to months at a time. The largest ones are known to be 50,000km and can be easily seen through a telescope with a proper filter.
 
 
 
 
 
Another interesting solar phenomenon which can be observed is the solar prominence. These are large loops of plasma which stream out off of the Sun’s surface due to magnetic fields. These prominences are not as bright as the sun’s surface and are located in the dimmer corona of the Sun. They require either expensive solar H-alpha filter to be seen or the more and more popular designated solar telescope.

Solar Events

Other than just viewing the Sun normally during the day, there are some extra exciting times to view it. The two inferior planets, Mercury and Venus, on occasion cross the Sun’s area in the sky with their orbital paths. When this occurs this is called a transit and when viewed properly appears as a dark circle blocking a small portion of the Sun’s light. Because the orbits of Mercury and Venus are tilted with respect to ours, transits of these two planets are rare, as not only do their orbits have to line up with ours, but they must at a point in their orbits that is level with ours as well. Mercury’s transits happen around a dozen or so times per century while, Venus with its slower orbit has transits that occur only twice in a hundred years. For transit dates check the calendar on the main page.

Solar eclipses are a transit of the Moon across the Sun and are much more common than the planetary transits mentioned above. For more on Solar eclipses click here.

Methods for Viewing the Sun

Pinhole Camera

The most basic way to view the Sun which can be done with household materials is to make a pin hole projector. This can be done with two pieces of stiff white paper and a pin or similar sharp object. Create a small hole in one of the sheets of paper using the pin. Let the Sun’s light shine through the hole onto the second piece of paper. An image that is safe to view will be projected onto the surface of the paper. Experiment with the size of the hole as well as the distance between the sheets of paper to obtain the best results. Additionally there are more sophisticated designs that can be made which can actually be a fun project.

Optical Projection

Another way to project a viewable image of the Sun onto a piece of paper is with an optical aid such as a pair of binoculars or a telescope. Without looking through the device, point it at the Sun and align the eyepiece a short distance from the sheet of paper; adjust this distance to focus the image. The best way to align your telescope or binoculars with the Sun is to look at the shadow. Although this method will produce a clearer projected image, you will run a small risk of damaging your equipment. While viewing this way for short periods of time should present no problems, lots of heat can be channeled through the lenses and prolonged use can cause cheaper plastics to melt.

Solar Glasses

Another popular method for viewing the Sun, is through solar filtered glasses. These are different from sun glasses and allow one to view the Sun rather easily without risking sight loss. These glasses are available for a rather low price, but don’t provide as clear a view as some of the other methods mentioned. Solar glasses at Amazon.com

Filters/Solar Telescopes

For those who simply must look directly at the Sun without projecting it there are several filters for binoculars and telescopes as well as telescopes specifically designed for looking at the Sun. Obviously these methods will cost you some extra money to make the necessary investments in, but they are worth it to many who find the Sun to be the most fascinating object in the sky to observe. One thing to be wary of is filters that are installed on the eyepiece of your telescope. These types are known to fail quite often, and it is very strongly recommended that if you come across one of these you do not use it. Proper solar filters are attached to the objective lens of the telescope or pair of binoculars. Additionally it is also important to examine solar filters for telescopes before each use as cracks or worn surfaces that could let light in could potentially be dangerous. This is the best way to observe the Sun and will give you the most detailed view of the Sun’s surface. Solar filters can be bought online for any size telescope. (Solar filters at Telescopes.com)

Solar telescopes are telescopes specifically designed to be used for viewing the Sun. If you find that you’ve caught “Solar Fever” and you are primarily interested observing the Sun a nice solar telescope is highly recommended. Additionally they are a more economical choice than buying an H-alpha filter which can cost upwards of a thousand dollars. There are several popular models on the market today many of which are very reasonably priced. Click below to check out some of these solar telescopes at Telescopes.com.