INDEX

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absolute field of view, 433–435, 509

absolute time, 383–384

absolute visual magnitude, 319–320

absorption lines, 323

accretion disk, 235–236

achromatic lens, 429

achromatic objective, 510

action-reaction, 443, 482

aerolites, 278–279

airglow, 437, 521

air turbulence, 436

albedo, 160, 185, 245, 253

Aldebaran, 49–50, 80–81

Alpha Centauri, 322

Alphecca, 70

Altair, 42–43, 75–76

amino acids, 247–248

analog image, 440

Andromeda, 26, 44, 45–46, 77–78

Angstrom, 449

Antarctica, 207–208

Antares, 41–42, 74

antimatter, 101, 343, 345–347, 485–486

antineutron, 346–346, 485–486

antiparticle, 345, 485–486

antiproton, 345, 486

aphelion

of Earth, 98

of Mercury, 126

of Venus, 128

Aphrodite, 142

apochromatic objective, 510

apogee, lunar, 90

Apollo 11, 134, 480

apparent field of view, 429

apparent visual magnitude, 319–320

Apus, 62–63, 66–67

Aquarius, 46–47, 78

Aquila, 42, 74–76

arc minutes, 5

arc seconds, 5

Arcturus, 38, 70–71

Ariadne, 37

Ariel, 253–254

Aries, 44–45, 76–77

Armstrong, Neil, 481

Arsia Mons, 153

artificial gravity, 131, 137–138, 489–490

Ascraeus Mons, 153

asteroid, 262

asteroid belt, 261–262

astronomical unit, 172

astrophotography, 439–440

attitude, 529

Auriga, 35–36, 82–83

aurora, 459

aurora australis, 105

aurora borealis, 105

autumnal equinox, 17, 18

axis of rotation, 4

az-el, 13–15

az-el mount, 523–524

azimuth, 13–14, 54

azimuth bearing, 523

azimuth/elevation, 13–15

Azores-Bermuda high, 176

Barlow lens, 517–519

barred spiral galaxies, 365–367

basaltic rock, 201

Beila’s Comet, 272

Bell, Jocelyn, 350

beta particles, 394

Betelgeuse, 48–49, 80–81

Betelgeux, 48–49, 80–81

big dipper, 29–30

binary star, 327

binocular telescope, 506

binoculars, 504–508

basic structure of, 504–505

field of view in, 507–508

optics in, 506–507

size specifications of, 505–506

black hole, 335, 354–360, 375, 376–379, 471

black dwarf, 348, 471

blackbody, 464–465

blackbody radiation, 464–465

blue shift, 363

blue supergiant, 327

Bode, Johann E., 261

Bode’s law, 261–262

Bolton, J., 457

Bootes, 38, 70–71

Brahe, Tycho, 230

Bruno, Giordano, 229

buddy system, 489

butterfly effect, 168, 327

Callisto, 243–244, 246

Caloris Basin, 127

Cancer, 35, 69

Canes Venatici, 38–39, 70–71

Canis Major, 48, 79–80

Canis Minor, 35, 69

Cannon, Annie, 324

Canopus, 66, 320

Capella, 36, 82–83

Capricorn, 40, 72–73

Capricornus, 40, 72–73

carbonaceous chondrite, 160

Carina, 66

cartesian coordinate plane, 54

Cassegrain reflector, 431

Cassiopeia, 26, 30

Castor, 35–36, 82

celestial latitude, 9–12

celestial longitude, 9–12

celestial resources, 479

Celestron, 27, 181, 186

Cepheid variable, 330, 370

Cepheus, 30–31, 330

Ceres, 262

Cetus, 44–45, 46, 76–77

Chameleon, 66–67

charge-coupled device, 440–441

Charon, 96, 189–191, 255–256

chemical rocket, 482–483

chromatic aberration, 429

circumpolar constellations

northern, 27–33

southern, 61–67

clock drive, 527–528

cloud chamber, 473

coma

in telescope, 511

of comet, 164, 265–266

Coma Berenices, 44

coma corrector, 511

comet, 260–273, 277

anatomy of, 263–273

apparition of, 265

burnouts, 270–272

coma of, 264, 265–266

core of, 264

flare-ups, 270–272

lifespans, 272–273

meteor showers and, 277

nucleus of, 264, 265

orbit of, 265

periodic, 265

tails of, 264, 267–268

compound lens, 429

computerized drive, 528–529

concave lens, 424–425

concave mirror, 426–427

conjunction, 100, 124–125, 147

inferior, 100, 125

superior, 124–125

constellations, 25–51

circumpolar, 27–33

of northern-hemisphere autumn, 44–47

of northern-hemisphere spring, 33–39

of northern-hemisphere summer, 39–44

of northern-hemisphere winter, 48–50

of southern-hemisphere autumn, 67–71

of southern-hemisphere spring, 75–79

of southern-hemisphere summer, 79–83

of southern-hemisphere winter, 71–75

converging lens, 422–424

convex lens, 422–424

convex mirror, 425–426

coordinates, southern, 53–59

Copernicus, Nicolaus, 229–230

corona, 332

Corona Borealis, 37–38, 70

corpuscular theory, 447

corrector plate, 512

Corvus, 39, 70–71

cosmic particles, 472–474

cosmic radiation, 494–495

CP1919, 350, 352

Crater, 39, 70–71

craters, 274–275

cross hairs, 517

crust, of Earth, 201

Crux, 62–63

Cygnus, 42, 74–76

Cygnus A, 457

D layer, 204–205

dark matter, 369

dark nebula, 338

Darwin, Charles, 287

December solstice, 59–60

declination, 15–21, 54–57

declination bearing, 524

deferent, 227–228

degrees, 4–6

Deimos, 147, 158–159

Deneb, 42–43, 75–76

deoxyribonucleic acid, 287

diffraction grating, 438

digital image, 440

dinosaurs, 289–290, 303

Dione, 249–250, 251

Dionysus, 37

directivity, 454

dispersion

in deep space, 352–353

in optics, 421–422

diverging lens, 424–425

diversity effect, 373

Dobsonian mount, 525–526

Dog Star, 48

Doppler effect, 330, 371

Doppler shift, 350–351, 462

Draco, 31, 37, 72

Drake, Frank, 295, 301

Drake-Sagan formula, 301

Dubhe, 30

dust tail, 267

dwarf, 324, 326, 327

orange, 327

red, 327

white, 324, 326

E layer, 204–205

Earth, 195–209

Antarctica, 207–208

aphelion, 198

atmosphere, 203–205

crust, 201

inner core, 200–201

interior, 200–202

ionosphere, 204–205

jet stream, 204, 206

land masses, 203

life on, 286–294

mantle, 201

mesosphere, 204

North Atlantic Ocean, 206–207

oblateness, 199

oceans, 202–203

outer core, 200–201

perihelion, 198

precession of axis, 200

Sahara Desert, 208–209

stratosphere, 204–205

thermosphere, 204–205

troposphere, 203–205

year, day, and seasons, 197–199

eastern hemisphere, 8

eclipse, 105–109

lunar, 108–109

solar, 106–108

eclipsing binary, 329–330

ecliptic, 21–22

plane of the, 21

Einstein, Albert, 356, 374, 460–461

El Nino, 202

electrical field, 447

electrical flux, lines of, 448–449

electrolysis of water, 492

electromagnetic field, 447–450

electron, 344–345

electron rest mass, 393

electron shells, 345, 346

elevation, 13–15, 54

elevation bearing, 523

elliptical galaxies, 363–365

elongation, 100, 124

Eltanin, 31

EM spectrum, 450–453

emission nebula, 339, 468

emission wavelengths, 438

Enceladus, 249

entropy, 284–285

epicycle, 227–229

equator, 4

equatorial orbit, 139

equinox

autumnal, 17, 18

March, 55–56

September, 55–56, 59

vernal, 17

equivalence principle, 396–397

Epsilon Eridani, 50, 82

erect image, 427

Eridanus, 49–50, 82

escarpments, 134, 275

Euclidean space, 357

Europa, 245–246

event horizon, 354–355

evolutionary spiral, 289–290

exit pupil, 506

expectation phenomenon, 365

extraterrestrial life, 478

extreme ultraviolet, 466–468

eye relief, 513

eyepiece, 427–428, 432, 513–515

focusing mount for, 514

Kellner, 514–515

orthoscopic, 514–515

outside barrel diameter of, 514

Plossl, 515

Ramsden, 514–515

Ezekiel, Book of, 300

F layer, 204–205

F1 layer, 204–205

F2 layer, 204–205

field of view

absolute, 433–435, 509

apparent, 429

in binoculars, 507–508

finder scope, 517

first quarter moon, 90–93

“fist rule,” 62

focal length, 423

focal point, 422–423

focal ratio, 434, 508–509

focal reducer/corrector, 519

focus, 422–423

fork mount, 523

fork mount/wedge, 524–525

Formalhaut, 46–47, 79

fovea, 504

Fowler, W. A., 369

f-ratio, 434, 508–509

Fraunhofer lines, 323

frequency, 448–449

full moon, 91–93

full-aperture solar filter, 520

fully multicoated optics, 507

fusion engine, 484–485

Gaia hypothesis, 200

gain, 454

Galatea, 188

galaxies, 363–371, 377–379

barred spiral, 365–367

clusters of, 367–368

elliptical, 363–365

Hubble classifications, 366

irregular, 365

radio, 369–370

spiral, 365–367, 377–379

Galilean moons, 242

Galilean refractor, 427–428

Galileo, 94, 104, 229, 242, 417

Galileo space probe, 244

gamma rays, 450, 472

Ganymede, 242–243, 246

gas tail, 267

gegenschein, 437

Gemini, 35–36, 82

Gemma, 70

general theory of relativity, 395–404, 460–461

geocentric theory, 226

geomagnetic field, 201

geomagnetic poles, 105

geostationary satellites, 11–12

German equatorial mount, 526–527

giant, red, 103, 324, 326, 329

gigahertz, 449

Global Positioning System (GPS), 528–529

Gold, Thomas, 353–354

gravitational assist, 133

gravitational constant, 357

gravitational radius, 356–357

gravitational waves, 359–360

gravity, as unit of acceleration force, 399

gray line, 443

Great Comet of 1744, 269

Great Dark Spot, 188

Great Nebula in Andromeda, 77–78, 458

Great Nebula in Orion, 49, 339

Great Red Spot, 175–176

Green Bank formula, 301–306

greenhouse gas, 144

Greenstein, J. L., 372

Greenwich meridian, 8

Grus, 46–47, 79

half-open interval, 13

Halley’s comet, 260, 263, 265, 268, 272

ham operators, 453

hard ultraviolet, 466–468

Hawking, Stephen, 359

heliocentric theory, 229–233, 321

heliopause, 334

Henry Draper Catalogue, 324

Hercules, 26, 37, 72

hertz, 448

Hertzsprung, Ejnar, 325

Hertzsprung-Russell diagram, 325–326

Hewish, Anthony, 350

high tide, 95

horizontal-plane direction pattern, 455

hours (of right ascension), 18

Hoyle, F., 369

Hubble, Edwin, 364–367, 370–371

Hubble Space Telescope, 237, 372, 441–442

Humason, Milton, 370–371

Hydra, 39, 70–71

hydrogen-fusion theory, 102

Hydrus, 64–65

hypersphere, 495

hypotheses, 223–224

Iapetus, 248–249, 251

ideal coordinate system, 7

Ikeya-Seki, 268

image

analog, 440

digital, 440

erect, 427

inverted, 428

resolution, 504

index of refraction, 419–421

inferior conjunction, 100, 125

infrared, 323, 450

infrared spectrum, 463

infrared astronomy, 463–465

interference pattern, 438, 455

interferometry, 455–457

intergalactic distances, 370–371

intergalactic travel, 493–497

International Date Line, 8

interplanetary dust, 263

interplanetary travel, 488–493

interstellar travel, 493–497

inverse-square law, 134

inverted image, 428

Io, 244–245, 246

ion engine, 483–484

ionosphere, of Earth, 204–205, 452

irregular galaxies, 354

Ishtar, 142

Jansky, Karl, 453

Jastrow, Robert, 497

jet stream, of Earth, 204, 206

June solstice, 57–59

Jupiter, 171–176

belts, 175

atmosphere and weather, 175

composition, 173–174

Great Red Spot, 175–176

magnetosphere of, 174

major moons of, 242–246

radio emissions from, 459

year and day, 172–173

zones, 175

Kant, Immanuel, 236

Kellner eyepiece, 514–515

Kepler, Johannes, 99, 101, 230–231

Keplerian refractor, 428–429, 509–510

Kepler’s laws, 230–231

Kepler’s third law, 99, 101, 231

kilohertz, 448

Kuiper Belt, 192, 260–261, 266

Lagrange points, 250

Laplace, Pierre-Simon Marquis de, 236

Large Magellanic Cloud, 65

last quarter moon, 91–93

last perfect day, 334, 478

latency, 297–298, 306

latitude, 4–7

celestial, 9–12

law of reflection, 418–419

lens

achromatic, 429

compound, 429

concave, 424–425

converging, 422–424

convex, 422–424

diverging, 424–425

planoconcave, 425

planoconvex, 424

lens sag, 430

Leo, 34, 69

Lepus, 48, 79–80

Libra, 33, 67–68

libration, 90

light rays, 418

light sail, 487

light-gathering area, 423, 433

light-pollution-reduction (LPR) filter, 521–522

light-year, 232, 320–321

lines of electrical flux, 448–449

lines of magnetic flux, 448–449

little dipper, 28–29

lobes, 455

longitude, 4–5, 8

celestial, 9–12

long-period variable, 331

low tide, 95

Lowell, Percival, 153

luminiferous ether, 382

Luna, 87

lunacy, 97

lunar apogee, 90

lunar day, 95

lunar eclipse, 108–109

lunar filter, 520–521

lunar perigee, 90

lunar tidal wave, 96

Lyra, 42, 74–76

Lyttleton, Raymond, 264–265

M13, 37, 72

Magellan, 65

Magellanic Cloud, 64–65, 365

large, 65

small, 64

magnetic field, 447

magnetic flux, lines of, 448–449

magnetospheres, planetary, 491–492

magnification, 428, 432, 433

magnitude

absolute visual, 319–320

apparent visual, 319–320

Malthus, Thomas, 292

Malthusian scenario, 292–293

mantle, of Earth, 201

March equinox, 55–56

maria, 94, 134, 275–276

Mariner 4, 151–152

Mariner 10, 128

Mars, 147–169

atmosphere and weather, 152–153

canals, 153–154

interior, 150–151

life on, 153–154

moons of, 158–162

surface, 151–152

year, day, and seasons, 148–150

mass distortion, 392–395

matter, 343–347

matter-antimatter engine, 485–486

Medusa, 32

Mensa, 64–65

Merak, 30

Mercator projection, 21

Mercury, 123–128, 131–138, 460–461

median radius, 337

megahertz, 448

meridians, 4–5

mesosphere, 204

metal-deficient star, 338

meteor, 263

meteor orbits, 461–462

meteor showers, 276–278

meteoric dust, 263

meteorite, 263

meteoroid, 262–263, 490–491

meteoroid origins, 273–274

Michelson, Albert, 382

Michelson-Morley experiment, 382

micrometeoroid, 263

microwaves, 450

Mimas, 250

minutes of arc, 5

Mira, 76–77

Mira variable, 331

Miranda, 251

mirror

concave, 426–427

convex, 425–426

parabolic, 427

paraboloidal, 427

spherical, 427

model star, 331–332

Moon, 87–98, 460

Moon filter, 520–521

Morley, Edward, 382

multiple star, 327

Musca, 62–63

mutations, 287–288, 289

nadir, 13, 54

nanometer, 323, 449

natural satellite, 87

natural selection, 287–289

near infrared, 323

near ultraviolet, 323

nebula, 233, 338–340

dark, 338

emission, 339

planetary, 339–340

nebular theory, 233–238

Neptune, 186–189

composition, atmosphere, and weather, 187–188

Great Dark Spot, 188

moon of, 255–256

year and day, 186–187

19891NR, 188

neutron, 344

neutron star, 348–349, 471

new moon, 90–93

Newton, Isaac, 230, 417

Newtonian reflector, 430–431, 510–511

Newton’s third law, 443

night vision, 503

noctilucent clouds, 130

nodes, 455

North Atlantic Ocean, 206–207

north celestial pole, 11, 17, 53

north geographic pole, 4

northern hemisphere, 6

northern lights, 105

nuclear fusion, 101

OBAFGKM, 323–325

Oberon, 252–253, 254

objective, 427–428, 432, 435, 510

achromatic, 510

apochromatic, 510

oblateness, 173, 199

Octans, 66–67

Olympus Mons, 151, 152–153

one-way membrane, 356

Oort Cloud, 192, 260, 494

Ophiuchus, 42–44, 74–75

opposition, 148

optics, 417–422

optoelectronic sensor, 438

orange dwarf, 327

orbital resonance, 189–190, 249–250

order of magnitude, 450

organic chemicals, 247

organisms, 289

Orion, 26, 48–49, 80–81

Great Nebula in, 49, 80

Orpheus, 42

orthoscopic eyepiece, 514–515

outer planets, 171–192

Ozma, 295–296

ozone, 204

parabolic mirror, 427

paraboloidal mirror, 427

parallax, 12, 99, 321

parallels, 4–5

parsec, 321–322

particle accelerator, 394

partial lunar eclipse, 108

path loss, 462

Pavo, 64

Pavonis Mons, 153, 162–163

Pawsey, J. L., 455

pedestal support, 522–523

Pegasus, 45–46, 77–78

penumbra

of shadow, 106–109

of sunspot, 104–105

Pericles, 26

perigee, lunar, 90

perihelion

of Earth, 98

of Mercury, 126

of Venus, 128

period, 330

Perseus, 32, 46

phase

first quarter, 91–93

full, 91–93

inferior planets, 124–125

lunar, 90–93

new, 90–93

waning crescent, 91–93

waning gibbous, 91–93

waxing crescent, 90–93

waxing gibbous, 91–93

Phobos, 147, 159–161

photometer, 437–438

photon, 355, 447

photosensor, 437

photosynthesis, 287

Piazzi, Guiseppe, 262

Pioneer, 174

Pisces, 44–45, 76–77

Piscis Austrinus, 46–47, 79

pixel, 440

plane of the ecliptic, 21

planetary filter, 522

planetary nebula, 339–340

planetesimal, 235

planetoid, 262

planoconcave lens, 425

planoconvex lens, 424

Pleiades, 44, 49–50, 80–81, 336

Plossl eyepiece, 515

Pluto, 96, 189–191

atmosphere, 190

composition, 190

moon of, 255–256

year and day, 190

point of view, 384–386

pointer stars, 30

polar orbit, 136–137

Polaris, 28

Pollux, 35–36, 82

porro prism, 506–507

positron, 345–346, 485

power, 429, 432

precession, 200

prime meridian, 8

probability, 223–225

probability fallacy, 224

Procyon, 35, 69

proton, 343–344

protostar, 327

Proxima Centauri, 299

Ptolemaic model, 227–229

Ptolemy, 227

pulsar, 350–354

Pythagoras, 101

quasar, 358, 371–376, 471

quasi-stellar radio source, 372

R R Lyrae variable, 331

radar astronomy, 459–463

radiant, 277–278

radiation counter, 472–473

radiation sickness, 491

radio amateurs, 453

radio astronomy, 453–459

radio galaxy, 369–370, 457, 471

radio sky, 457–458

radio Sun, 458

radio telescope, 453–459

Ramsden eyepiece, 514–515

rays, 274–275

Reber, Grote, 453–454

red dwarf, 327

red giant, 103, 324, 326, 329

red-giant phase, 103, 334–335

red shift, 363, 371, 373–374

reflecting telescope

Cassegrain, 431

Newtonian, 430–431, 510–511

reflection, 418–419, 420

law of, 418–419

total internal, 420

refracting telescope

Galilean, 427–428

Keplerian, 428–429, 509–510

refraction, 419–421

index of, 419–421

refractive index, 419–421

Regulus, 34, 69

relativity, 381–404

general theory of, 395–404, 460–461

special theory of, 381–395

resolution, 432–433

resolving power, 432–433, 504

Reticulum, 64–65

reverse triangulation, 101–102

Rhea, 248, 251

ribonucleic acid, 287

Rigel, 48–49, 80–81

right ascension, 15–21, 54–57

right-ascension bearing, 524

Ring Nebula, 339

robot astronauts, 480–482

roof prism, 506–507

rotating-cloud theory, 234

Roy G. Biv, 323

Russell, Henry, 325

Ryle, Martin, 455

Sagan, Carl, 301

Sagittarius, 41, 73

Sahara Desert, 208–209

Sandage, A., 372

Saturn, 176–180

composition, atmosphere, and weather, 178–179

major moons of, 246–250

rings, 180

year and day, 177–178

Saturn booster, 482

Schmidt-Cassegrain telescope, 270, 512–513

Schwarzchild, Karl, 356

Schwarzchild radius, 356–357

scintillation, 350, 373

Scooter, 188

Scorpio, 33, 41, 74

Scorpius, 41–42, 74

Sea of Crises, 94

Sea of Tranquillity, 94

Search for Extraterrestrial Intelligence (SETI), 284, 295

seconds of arc, 5

sensitivity, 504

September equinox, 55–56, 59

Serpens, 42–44, 74–75

sferics, 453

shepherd moons, 186

Shklovskii, Iosif S., 369

shortwave, 452

sidereal day, 17, 57, 89

sidereal lunar orbital period, 89

siderites, 279

sighting device, 516–517

simultaneity, 381–385

singularity, 354

Sirius, 48, 79–80

Sky and Telescope, 502–504

skyglow, 269, 437

slew rate, 528

Small Magellanic Cloud, 64

soft ultraviolet, 467

solar wind, 174, 373

solar eclipse, 106–108

solar filter, 519–520

solar flare, 105, 133–134, 271–272, 491

solar tidal wave, 96

solar wind, 462

solstice

December, 59–60

June, 57–59

summer, 18

winter, 18

south celestial pole, 11, 17, 53, 62

south geographic pole, 4

southern coordinates, 53–59

southern cross, 62

southern fly, 62

southern hemisphere, 6

southern lights, 105

Soyuz booster, 482

Space Shuttle, 482

space telescope, 440, 442–443

space travel, rigors of, 157

spatial curvature, 398–399

spatial distortion, 390–392

special theory of relativity, 381–395

specific gravity, 177

spectra, stellar, 323–325

spectral classifications, 322–326

spectrograph, 438

spectrometer, 421–422, 438

spectrophotometer, 467

spectroscope, 130, 323, 438–439

spectroscopy, 104

speed of light, constancy of, 382–383

spherical aberration, 429

spherical mirror, 427

Spica, 34, 68

spiral galaxies, 365–367, 377–379

spiral nebulae, 363

Stanley, G., 457

star clusters

galactic, 336

globular, 336–338

open, 336

star diagonal, 516

star tracker, 443

stellar sail, 486–488

stellar spectra, 323–325

stellar wind, 328, 486

stereoscopic telescope, 506

Stickney, 161

stratosphere, of Earth, 204–205

sulfuric acid virga, 142

summer solstice, 18

summer triangle, 42–43, 75

Sun, 98–109, 333–334, 469, 477–478

Sungrazers, 268

sunspots, 104–105

superclusters, 369

supergiant, 326, 327

blue, 327

white, 327

yellow, 330

superior conjunction, 124–125

supernova, 233, 329, 468

synchronous-orbital radius, 159

synchrotron radiation, 459

synodic day, 17, 57, 89

synodic lunar orbital period, 88–89

Tau Ceti, 45, 76

Taurus, 49–50, 80–81

tectonic plates, 276

tektites, 279–280

teleoperation, 480

telepresence, 480–482

telescope

absolute field of view of, 509

accessories, 513–522

aperture of, 508

Cassegrain reflector, 431

choosing, 508–513

focal ratio of, 508–509

f-ratio of, 508–509

Galiliean refractor, 427–428

Keplerian refractor, 428–429, 509–510

Newtonian reflector, 430–431, 510–511

normal-field, 510

rich-field, 510

Schmidt-Cassegrain, 511–512

terahertz, 449

terminator, 443

Tethys, 250, 251

theories, 223–225

thermosphere, of Earth, 204–205

The War of the Worlds, 154

three-space, 357

tidal theory, 232–233

tidal wave

lunar, 96

solar, 96

tides, 94–97

high, 95

low, 95

time dilation, 299–300, 386–390, 400–401, 485, 495–497

Titan, 247–248, 251

Titania, 251–252, 254

Titius, Johann D., 261

total internal reflection, 420

total lunar eclipse, 108

total solar eclipse, 108

transit, 125

Triangulum, 62–63

Triangulum Australis, 63

tripod, 522

Triton, 255–256

troposphere, of Earth, 203–205

tsunami, 96

Tucana, 64–65

twilight line, 443

Tycho, 279

ultraviolet, 323, 450, 466–469

extreme, 466–468

hard, 466–468

soft, 467

sources of, 468–469

umbra

of shadow, 106–109

of sunspot, 104–105

Umbriel, 253, 254

Uranus, 180–186

composition, atmosphere, and weather, 184–185

major moons of, 250–254

rings, 185–186

year, day, and seasons, 182

Ursa Major, 29–30

Ursa Minor, 28–29

Van Allen radiation belts, 248, 491

variable star, 329–331

Cepheid, 330

eclipsing binary, 329–330

long-period, 331

Mira, 331

RR Lyrae, 331

Vega, 42–43, 74–76

Venera probes, 129

Venus, 123–125, 128–132, 139–144, 460

vernal equinox, 17

Virgo, 34, 68

virtual reality, 480

visible light, 450

visual magnitude, 269

Volans, 66

Voyager, 174, 176, 182, 184, 185, 188

waning crescent moon, 91–93

waning gibbous moon, 91–93

War of the Worlds, 154

wavelength, 449

waxing crescent moon, 90–93

waxing gibbous moon, 91–93

Weather Underground, 15, 27, 61, 181, 186, 503

Wells, H. G., 154

western hemisphere, 8

Whipple, Fred, 264

white dwarf, 324, 326

white hole, 376

white supergiant, 327

winter solstice, 18

x-ray stars, 471

x-ray telescope, 470

x-rays, 450, 469–472

yellow supergiant, 330

zenith, 9, 54

zero-g, 490

Zeus, 35, 82

NUMBERS

19891NR, 188