Observing the Sun for Yourself
Don't ever look directly at
the Sun through a telescope unless you have the proper filters.
Can one damage their eyes by looking directly at the Sun?
There are several ways you can observe the Sun, and hopefully sunspots,
for yourself. The easiest and safest is to project the Sun by building
your own pinhole camera. Or, if you have your own telescope, you will
need to obtain a solar filter. There are even solar telescopes online,
which you can access via the web to observe the Sun.
Projecting the Sun | Using
the little Sunspotter Telescope | Remote Telescopes
| Using Your Own Telescope | Observing
Solar Eclipses | Comparing Your Sunspot Drawings
| Other Pages
Projecting the Sun
You can easily and safely observe the Sun by projecting it through a tiny
hole onto a white sheet of paper. This simple device is called
a "pinhole camera".
You'll need:
- 2 sheets of stiff white paper
- A pin
- A sunny day
- Perhaps a friend to help
With the pin, punch a hole in the center of one of your pieces
of paper. Go outside, hold the paper up and aim the hole at the Sun.
(Don't look at the Sun either through the hole or in any other way! )
Now, find the image of the Sun which comes through the hole.
Move your other piece of paper back and forth until the image looks best.
What you are seeing is not just a dot of light coming through the hole,
but an actual image of the Sun!
Experiment by making your holes larger or smaller. What happens
to the image?
What do you think would happen if you punched a thousand holes in
your paper, and you put little lenses in front of each hole to
refract (e.g. bend) the solar images to all fall on top of each
other. What do you think you'd see?
In fact, optical telescopes can be
thought of as a collection of millions of "pinhole" images all
focused together in one place!
You can also project an image of the Sun using a pair of binoculars
or small telescope:
Projecting the Sun (via binoculars) (adapted from Society for Popular Astronomy SPA)
Projecting the Sun (via telescope)
The Sun (Dark Sky Insitute)
Observing the Sun for Yourself (PDF)
If you want, you can make your pinhole camera fancier by
adding devices to
hold up your piece of paper, or a screen to project your Sun
image onto, or you can even adapt your pinhole camera into
a "real" camera by adding film.
If you want to learn more about how light works,
you can join artist Bob Miller's web-based "Light Walk" at the Exploratorium.
It's always an eye-opening experience for students and
teachers alike. His unique discoveries will change the way you look
at light, shadow, and images!
Bob Miller's Light Walk
Using the little Sunspotter Telescope
A safe and inexpensive solar telescope of your own! Thanks to the efforts of
Learning Technologies, Inc., who brought you the Starlab portable planetariums
and the Project Star kits, schools can now own
solar telescope of their own.
This wooden, folded-path, Keplerian telescope provides a much safer and
convenient way to view the brilliant light of the Sun than other more
common methods. By using a series of mirrors, the device projects a
bright 3.25-inch solar image onto a 5-inch white viewing screen through
a powerful 62mm diameter objective lens. In its perfectly curved cradle,
the Sunspotter is easily aligned to the Sun in seconds, without the
complication of telescopes, solar filters, and tripods.
The Sunspotters run approximately $300. Details can be found at
the Sunspotter website.
Using Remote Solar Telescopes
Using Mike Rushford's robotic solar observatory in Livermore, California,
you can actually control your realtime view of the Sun by
controlling this telescope from your web browser.
At cloudy times, there are other things to do as well!
Eyes on the Skies
Using Your Own Telescope
The safest way to look at the Sun through your own telescope is NOT to!
Not only could you damage your eye, but you can also damage the
lenses in the telescope.
The safest practical way to see the Sun is by eyepiece projection.
Line up your telescope with the Sun, but
instead of looking through the eyepiece,
hold a sheet of white paper behind the eyepiece.
You'll see a solar image projected onto the paper.
What happens when you move the paper farther back?
Experiment with the paper for a sharp viewing
contrast. You should be able to see the largest sunspots
with this method.
Viewing the Sun with a Telescope
Dr. Sunspot gives more detailed information about viewing the Sun with a
telescope and filters.
Understanding Hydrogen-Alpha Solar Filters
This site is designed to help educate you on the basics
of front and rear mounted Hydrogen-Alpha (Ha) filters, what you
can see through them, and assist you in
making an educated choice when/if it comes time to buy.
Observing the Sun in H-Alpha
This site give technical information on how to observe the Sun with your own
telescope using an H-alpha filter.
Observing Solar Eclipses
A solar eclipse occurs when the Moon, during its monthly revolution around
the Earth, happens to exactly line up between the Earth and the Sun.
Then shouldn't there be an eclipse every month?
Solar eclipses do occur at New Moon, but not at every New Moon.
Most often the Moon passes a little higher or a little
lower than the Sun. There is a solar eclipse about twice a year,
when the Moon's and Sun's positions exactly line up.
The glory of a solar eclipse comes from the dramatic view of
the Sun's corona, or outer atmosphere, which we can see only
when the brilliant solar disk is blocked by the Moon.
The corona is not just light shining from around the disk.
It is actually the outermost layer of the solar atmosphere.
Although the gas is very sparse, it is extraordinarily hot
(800,000 to 3,000,000 K), even hotter than the surface of the Sun!
(The heating of the corona is still a mystery.)
The corona shows up as pearly white streamers, and their shape
is dependent upon the Sun's current
magnetic fields. Thus every eclipse will be unique and
glorious in its own way.
When there is a solar eclipse, it is only visible from a small
area of the Earth. It's unlikely that, during your lifetime,
you will ever have a total solar eclipse right where you live.
However, many people travel long ways to experience a total
solar eclipse. Or, if you're lucky, you might be able to see a
partial solar eclipse (one where the Moon doesn't quite cover
all the Sun's disk) nearby someday.
You can safely observe a TOTALLY eclipsed Sun with your eyes.
However, for observing the beginning and ending of an eclipse,
or for a partial eclipse, you will need a pinhole camera,
an appropriate type of welder's glass,
or special Mylar glasses to observe the Sun safely.
Solar Eclipse Observing Exercises.
Solar Data Anaylsis Center Eclipse Information
Eclipse Paths
Sunspot Drawings
Until recently, astronomers have had to rely on drawings or sketches
to document what they've seen. The world of CCD cameras and other
technological wonders has changed all that. However, historic drawings
are still very important. And even today, drawings are still more
accurate at recording exactly what the eye sees, unaltered by the
processing of fancy electronics.
Drawings of sunspots have been done for hundreds of years. Galileo's
drawings still survive today. And, the solar telescope at Mt. Wilson,
above Pasadena, California, has been collecting sunspot drawings since
1917. This tradition still continues. You can check the current
sunspot drawings each day, and compare them with your own:
Daily Sunspot Drawings at Mt. Wilson.
Galileo's Sunspot Drawings.
