- George Ellery Hale (1868-1938)
- Born in USA.
- He was the first to recognize the importance of the magnetic fields of sunspots.
- He invented the spectoheliograph.
- He was responsible for having the largest reflector telescopes in the US set up.
- Born in England.
- He drew the first good star map of the southern stars.
- He completed a study of the movements of the Moon.
- He probably is best known for his work on comets, one of which is named after him.
- Born in Germany.
- He discovered the planet Uranus.
- He was the first to work out the shape of a galaxy.
- He established that double stars are binaries.
- He discovered star clusters and nebulae and made observations on the planets.
- Born in Denmark.
- He found that red stars are either giants or dwarves, but not in-between.
- He drew a diagram (H-R) according to the luminosity and colour of stars.
- He devised a method of estimating stellar distances by examination of the spectra of the stars.
- Born in Poland.
- He built quadrants, sundials, and telescopes.
- He produced the best lunar map of his day.
- Born in England.
- He correctly predicted that Mercury and Venus would transit across the face of the sun in 1631.
- Born in USA.
- He proved that the starry nebulae are independent galaxies.
- He divided galaxies into classes according to their shapes.
- He found that there is a link between the distance of a galaxy and the speed in which it is moving away.
- Born in England.
- With the aid of a spectroscope on his telescope, he found dark lines on the spectra of Betelgeuse and Aldebaran and other stars. Thus, he determined that Sirius is moving away by noting red-shifting.
- He showed that the nebulae are gaseous and that the planets shine by reflecting light from the Sun.
- He also obtained photographic stellar spectra.
- Born in Holland.
- He discovered what the rings of Saturn are.
- He also discovered Titan, one of Saturn’s satellites.
- He made the first drawing of Mars that showed the surface detail.
- Numerous lenses and clocks were made by him.
- His main contribution to science was his belief that light is a wave motion.
Edmund Halley (1656-1742)
William Herschel (1738-1822)
Ejmar Hertzsburg (1873-1967)
Johannes Hevelius (1611-1687)
Jeremiah Horrocks (1619-1642)
Edwin Powell Hubble (1889-1953)
William Huggins (1824-1910)
Christiaan Huygens (1629-1695)