1. Learn about sun safety.
Never view the sun with the naked eye, or with any unfiltered optical device, such as binoculars or a telescope. It’s extremely dangerous! One safe way to observe sunspots in your backyard is to project an image of the sun through a telescope and onto a piece of white poster board.
2. Gather your materials.
Gather what you’ll need, including a telescope, a piece of cardboard, tape, white poster board, and scissors.
3. Build a sun projector.
Look at the illustration "Telescope Projector" or the illustration "Binocular Projector" for reference as you build your sun projector. Set up your telescope as if you were looking at the sun, but remember to never look directly at the sun.
- Make a cardboard collar to fit around the front end of the telescope or binocular, as shown in the illustrations. This shades the area where the image will appear from sunlight. And, in the case of binoculars will cover the lens, which you will not use.
- Focus the telescope or binocular on infinity by looking at a distant object (not the sun!) in the normal way. (If you are using a telescope, use a low-magnification eyepiece.)
- Point the telescope or binoculars at the sun (do not look through the instrument to do this), as shown in the illustrations, and adjust the direction the instrument is pointing until the image of the sun appears on the screen. Note that this may take a minute or two. One useful trick is to watch the shadow of the binoculars or telescope tube: if pointed directly toward the sun, then the sides of the tube will cast no shadows, and the instrument's shadow will be as small as it can be.
- Move the screen toward or away from the eyepiece until the image of the sun fits neatly in the middle. Adjust its tilt until the sun’s image is circular.
- Jiggle the telescope or binoculars very slightly. Any specs on the image of the sun that do not jiggle along with the image when you do this are specks in the telescope or binoculars, or smudges on the screen, and not spots on the sun itself.
4. Project the image of the sun and trace sunspots.
Tack a piece of white poster board to a building or tree. If neither is available, you can also use an adjustable music stand. Focus the image of the sun onto the piece of white poster board. If the distance and focus are correct, on the paper you should see a circle of light (the disk of the sun) that is brighter at the center and darker around the edges. Adjust the distance between the paper and the telescope until the disk is about the size of a small paper plate. The image will probably be blurry; focus your telescope until the circle becomes sharp. Inside the circle you should see some small dark spots, which are sunspots. Trace the perimeter of the sun and any sunspots that you see on the paper.
5. Share and discuss your findings.
Show a family member what you were able to see. Work together to have them repeat the steps the next day, and then compare your drawings of the sun and sunspots to see how similar or different they are. If possible, track the sunspots over ten days. Then talk about it. Have the sunspots moved? Have their shapes and sizes changed? Are there fewer sunspots? More? Finally, talk about why sunspots are useful for information about the sun. Sunspots can serve as markers to help you see the sun’s rotation.
Why is it extremely dangerous to look directly at the sun?
Materials You Provide
- Aluminum foil
- Sewing needles or push pins
- Shoeboxes, or 2-foot rectangular cardboard boxes
- Telescope or binoculars
- Transparent tape
- White paper
- White poster board
The resources are also available at the top of the page.
- Internet Access: Required
- Tech Setup: 1 computer per classroom, Projector, Speakers
- Plug-Ins: Flash
Recommended Prior Activities
The sun is responsible for all life on Earth; it gives us light and heat. The sun is not a solid body; it is a giant ball of gas, made mostly of hydrogen and helium. The surface of the sun is called the photosphere. Sunspots are cooler regions on the sun, caused because of a strong magnetic field. Sunspots appear dark only because they are not as hot or bright as the area surrounding them.
Term Part of Speech Definition Encyclopedic Entry atmosphere Noun
layers of gases surrounding a planet or other celestial body.
Encyclopedic Entry: atmosphere chord Noun
straight line segment joining and included between two points on a circle.
transfer of heat by the movement of the heated parts of a liquid or gas.
width of a circle.
Kelvin scale Noun
scale for measuring temperature where zero Kelvin is absolute zero, the absence of all energy.
magnetic field Noun
area around and affected by a magnet or charged particle.
lowest visible layer of a star and the boundary from which the star's diameter is measured.
dark, cooler area on the surface of the sun that can move, change, and disappear over time.
For Further Exploration