The Astronomy Handbook by Govert Schilling

Author:Govert Schilling [SCHILLING, GOVERT]
Language: eng
Format: epub
Publisher: Running Press
Published: 2024-05-28T00:00:00+00:00

WILLIAM HERSCHEL BELIEVED THAT THERE WAS A LINK BETWEEN THE NUMBER OF SUNSPOTS IN A GIVEN YEAR AND THE PRICE OF GRAIN.

IN THE DISTANT FUTURE, A YEAR LASTS LONGER: WHEN THE SUN LOSES MASS, THE EARTH WILL DESCRIBE A WIDER AND SLOWER ORBIT.

ARTISTIC SPOTS A drawing of sunspots made in 1983 at the Allegheny Observatory in the United States.

SHIMMERING PROTECTION Aluminized mylar makes one of the safest solar filters.

HOW TO LOOK AT THE SUN SAFELY

Despite the distance of 93 million mi. (150 million km) separating the Sun from the Earth, the Sun is so bright that it can cause permanent damage to the human retina, especially when binoculars or a telescope are used for viewing. Special precautions are therefore required to observe the Sun. Preferably use eclipse glasses to view the Sun with the naked eye. Eclipse glasses are normally used for observing solar eclipses (see here): during the partial phase of a solar eclipse the non-eclipsed part of the Sun is still far too bright to view without protection. But of course, eclipse glasses also work when there is no eclipse. Eclipse glasses can be purchased for a few dollars at public observatories or planetariums.

Alternative filters, such as silver packaging material, a CD, a piece of glass blackened with a candle, or a stack of old photographic negatives are much less safe. The filtering effect is not always constant and, moreover, not all harmful infrared and ultraviolet radiation from the Sun will be blocked. Although these types of radiation are invisible, they can also damage the retina.

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