Amateur astronomer: observing sun spots

To gain knowledge of what a star is, every amateur astronomer will at some point want to observe our sun.

Photo Credit: Mark Bond
By Michael Merrill

At some point, every amateur astronomer should do some observing of the sun. Since the sun is the closest star to Earth, an amateur astronomer can learn a great deal from observing the different phenomenon that happens on and around the sun. These phenomenon’s include sunspots, solar flares, solar corona, and eclipses. There are some very important and useful tips every amateur astronomer needs to know before attempting any solar observations.

It is important for any amateur astronomer to know what the different solar phenomenon’s are and when they are viewable. A solar eclipse is an event where the moon gets between the earth and the sun. Eclipses are highly predictable, however infrequent events. Since they are predictable, it is possible to be set up and ready to view the eclipse before it occurs. The solar corona is the sunlight that is left visible during a full solar eclipse, when the sun is totally blocked out. Devices allowing for the viewing of the solar corona do exist, however they are normally far too expensive to be practical for an amateur astronomer. Sunspots are a feature of the sun, often thought of as solar clouds. They are the by-products of the extremely high temperature reactions taking place in and around the sun. Sunspots are always present and therefore easily viewable. Solar flares are a discharge of material from the sun and are very irregular and highly unpredictable. For the amateur, getting to view a solar flare takes being in the right place at the right time. Typically, only professional observatories can react quickly enough to fully view a solar flare.

WARNING: Never attempt to observe the sun with the naked eye, especially with binoculars! Severe damage and blindness will result!

The most common way to observe sunspots is with binoculars. Binoculars can be used to project an image of the sun onto a piece of paper. Projecting a focused image of the sun takes minimal preparation. To begin you will need a pair of binoculars, a tripod, a couple pieces of cardboard, and a sheet of white paper (to use as a screen). First, attach the binoculars to the tripod. Next, it is necessary to cut two holes in one of the pieces of cardboard ensuring that they are big enough to accommodate the binoculars’ front lenses. Then using duct tape, attach the new cardboard shield to the front of the binoculars. This cardboard shield is necessary to create a shadowed background for the sun’s projected image. With the cardboard shield in place, point the binoculars at the sun. Use the remaining piece of cardboard as a backing for the white paper. The white paper makes a great viewing surface.

WARNING: Focused sunlight can become dangerously hot! Do not place anything flammable near the binoculars! Also, long periods of exposure to direct sunlight and high temperature will cause damage to and possibly irreparable damage to the lenses.

Hold the viewing surface about 12 inch from the binoculars. The sun’s image should know be seen on the viewing surface. Adjust the focus as necessary.

I would like to pass on a word of warning about pointing a telescope at the sun. I have personally witnessed what happened when a friend of mine tried to use an 8 inch refracting telescope to project the sun’s image. Within 5 minutes, the projected image burnt a hole in the screen and had managed to melt his telescope’s $200 eyepiece! The only truly safe method of observing the sun with a telescope is with a sun filter. Never point a telescope at the sun without one! A sun filter is roughly as dark as an arc welder’s mask. The filter fits onto the telescope in place of the main lens cap, through which it is then possible to view the sun’s image directly and safely through the eyepiece. This is the best way to fully see and appreciate the unique phenomenon of the sun, such as sunspots.

By using either of the two methods discussed above to observe the sun, one can safely enjoy fantastic views of the different solar phenomenon that otherwise would be unavailable to us.

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