What Instrument is Used to Observe Sunspots?

Identification

• Scientists theorize that sunspots occur when coils of magnetic fields rise onto the solar surface from underneath. Sunspots appear as darker regions because their energy is reduced and they are cooler than the surrounding areas.

  Sunspots release solar flares, which cause the Aurora Borealis (Northern Lights). During these events, charged solar particles reach the Earth's magnetosphere and react with gases in the upper atmosphere.

  Solar activity creates a wide spectrum of electromagnetic noise and can interfere with radio signal reception and transmission.

Types

• Solar telescopes are used by professional astronomers both on earth and on satellites. These instruments differ from other optical telescopes because they do not need to collect light and also must deal with the heat from the object they focus on. The telescopes are very large.

  In addition, astronomers observe the sun with radio telescopes because radio emissions provide important diagnostic information about the sun's magnetic field.

  Amateur observation of sunspots usually involves an indirect view by using projected images or a direct view through protective filters designed particularly for solar viewing. Very dark filter glass or hydrogen-alpha filters can be placed on the front of a telescope to provide safe direct observation.

  Amateurs also use smaller versions of solar telescopes such as the spectrohelioscope, which passes light through a diffraction device such as a prism and allows a way of looking at the sun's surface through a complicated methodology.

Warning

• No one should ever look directly at the sun, because this can cause eye damage.

History

• Hans Lipperhey of the Netherlands invented the telescope in 1608. Several astronomers began studying sunspots with a telescope soon after, including Thomas Harriot, David Fabricius, Christoph Scheiner and Galileo Galilei.

  With his new telescope, Galileo discovered Jupiter's four largest moons (now called the Galilean satellites) and the craters on Earth's moon and viewed dark regions on the sun. These blemishes on the moon and sun eventually brought Galileo trouble with the Roman Catholic Church, which stipulated that all the heavenly bodies were perfect. In addition, he publicly agreed with the theory presented by Nicolaus Copernicus that the sun was the center of the solar system rather than the Earth. Galileo's pronouncements eventually made him a casualty of the Inquisition, and he was brought under house arrest in 1633, where he remained until his death in 1642 at the age of 78.

Time Frame

• The sun experiences 11-year cycles of activity undulating from minimum to maximum. During the latest maximum activity, in 2000, the largest sunspot seen in nine years was viewed, and it covered an area more than 12 times larger than Earth's entire surface. The largest known sunspot was viewed in 1947, and it was three times larger than the 2000 one. In 1989, a large sunspot generated enough magnetic activity to disrupt electric power transmission in Canada for several days.