ABSTRACT
The Sun, the controlling body of the Solar System, is the only star close enough to be studied in detail. It is 270 000 times closer than the nearest stars beyond the Solar System, those of the Alpha Centauri group. The first known estimate of the distance of the Sun was made by the Greek philosopher Anaxagoras. The first reasonably accurate estimate of the Earth–Sun distance was made in 1672 by G. D. Cassini, from observations of the parallax of Mars. One early method involved transits of Venus across the face of the Sun, as suggested by J. Gregory in 1663 and extended by Edmond Halley in 1678. The first photograph of the Sun–a Daguerreotype–seems to have been taken by Lerebours, in France, in 1842. Direct telescopic observation of the Sun through any telescope is highly dangerous, unless special filters or special equipment is used.
