Part 15

Andromeda nebula, 28 temporary star, 28, 29, 45

Apex, of solar motion, explained, 221

Aquila, constellation, temporary star in, 40

Arctic regions, position of pole in, 194

Argo, constellation, variable star in, 205

Association, international geodetic, 139

Asteroids, first discovery by Piazzi, 59, 106 discovery by photography, 64 group of, 63 photography of, invented by Wolf, 104

Astronomer, royal, 1 working, description of, 152

ASTRONOMER'S POLE, THE, 184

Astronomy, journalistic, 176 practical uses of, 112

Atmospheric refraction, explained, 193

Axis, of figure of the earth, 136 of rotation of the earth, 136 polar, of telescope, 173

Barnard, discovers satellite of Jupiter, 51

Bessel, measures Pleiades, 15

Bond, discovers crape ring of Saturn, 144

Bradley, observes at Greenwich, 219

Brahe, Tycho, his temporary star, 40

Bruce, endows polar photography, 197

Campbell, observes Pole-star, 18

Cape of Good Hope, observatory, photography at, 101 telescope, 170, 174

Capriccio, Galileo's, 55

Cassini, shows Saturn's rings to be double, 144

Cassiopeia, temporary star in, 40

Celestial pole, 184

Central sun theory, 223

Centre of gravity, 217

Chart-room, on ship-board, 5

Chronometer, invention of, 8