Part 22

Stability, of Saturn's rings, 145 of Solar System, 210

Standards, time, of the world, 111 table of, 130

"Standard" time, explained, 127

Star-catalogue, general photographic, 102

Star-clusters, photography of, 98

Star-distances 94, 106 measured with heliometer, 158 Rutherfurd, 94

Star magnitudes, 91

Star-motion, toward us, 21

Star-tables, astronomical, 118

Stars, variable, 42

St Gothard railway, tunnels, 220

Sun, newspaper, the moon hoax, 201

SUN-DIAL, HOW TO MAKE A, 69

SUN'S, DESTINATION, 210 distance, compared with star distance, 97 measured with Eros, 67, 106 motion, apex of, 221

Sun-spots, discovered by Galileo, 49

Systema Saturnium, Huygens, 143

Telescope, clock, 175 at Paris Exposition, 176, 180 double, for photography, 86 equatorial, explained, 170 first used by Galileo, 49 motion of, 87 mounting great, 170 unmoving, for polar photography, 197

TEMPORARY STARS, 37 in Andromeda nebula, 28, 29, 45 in Aquila, 40 in Cassiopeia, 40 in Perseus, 46 in Scorpio, 39 their number, 38 theory of, 42

Time, correct, determined astronomically, 113 differences between different places, 121

TIME STANDARDS OF THE WORLD, 111 standards of the World, table of, 130 system, in New York, 120 zones, explained, 128

Trails, photographic, 191

Transit, for determining clock error, 118

Tycho Brahe, his temporary star, 40

Ulugh Beg, early star-catalogue, 21

Undulatory theory, of light, 19, 148

Universe, theories of, 34, 53, 56

Uranus, discovered by Herschel, 59, 142

Use of occultations, 166, 167