The Observer's Year (eBook)

Preface 6
Contents 8
Introduction 10
Phases of the Moon 2005–2010 13
January 17
January 1 The January Sky 22
January 2 The Two Most Famous Constellations 23
January 3 The Poles of the Sky 24
January 4 The Quadrantid Meteors 25
January 5 The Horse and his Rider 25
January 6 The Faintest Star in the Plough 26
January 7 The Little Bear – and the Guardians of the Pole 27
January 8 The Legend of the Bears 29
January 9 Lunokhod 2 on the Moon 30
January 10 Colours of the Stars 30
January 11 Phases of the Inferior Planets 31
January 12 Orion, the Hunter 33
January 13 Orion as a Guide 34
January 14 The Legend of Orion 36
January 15 Betelgeux 36
January 16 Rigel 38
January 17 Comets 39
January 18 Hare in the Sky 39
January 19 The Dove, the Graving Tool and Declination 41
January 20 The Belt and the Sword 42
January 21 Features of the Moon 43
January 22 Right Ascension 44
January 23 Clusters in Cassiopeia 45
January 24 Variable Stars in Cassiopeia 46
January 25 Tycho’s Star 47
January 26 Northern and Southern Lights 48
January 27 King Cepheus 49
January 28 Variable Stars in Cepheus 50
January 29 The Celestial Lizard 51
January 30 Introduction to Eridanus 52
January 31 Lunar History 53
February 55
February 1 The February Sky 60
February 2 Oppositions of the Planets 60
February 3 Touchdown in the Ocean of Storms 61
February 4 Gemini 62
February 5 Fra Mauro 63
February 6 The Non-Identical Twins 64
February 7 William Huggins and his Spectroscopes 64
February 8 The Castor Family 65
February 9 Variable Stars in the Twins 66
February 10 Messier’s Catalogue – and M35 67
February 11 The Eskimo Nebula 68
February 12 Messengers to Venus 68
February 13 Introducing the Milky Way 69
February 14 The Solar Cycle – and Solar Max 70
February 15 Lunar Insects? 70
February 16 Touchdown on Eros 71
February 17 Missions to the Sea of Crises 72
February 18 Twinkling Stars 72
February 19 De Revolutionibus 73
February 20 The Great Dog 74
February 21 The Celestial Pup 76
February 22 The Sun’s Surroundings 77
February 23 Messier 41 77
February 24 Supernovæ 78
February 25 Fritz Zwicky and his Supernovæ 79
February 26 Procyon and the Little Dog 79
February 27 The Little Snake 80
February 28 An Equatorial Star 81
February 29 Leap Years 81
March 83
March 1 The March Sky 88
March 2 The Celestial Crab 88
March 3 Back to the Moon 89
March 4 The Seas of the Moon 90
March 5 The Beehive 91
March 6 Binoculars and the Sky 92
March 7 X Cancri 93
March 8 ‘The Solitary One’ 93
March 9 The Watersnake 94
March 10 The Giraffe and the Southern Pointers 95
March 11 The Planet-Hunter 96
March 12 Star Magnitudes 97
March 13 Solar System Anniversaries 98
March 14 The Greatest Globular Cluster 98
March 15 Choosing a Telescope 99
March 16 Procyon 100
March 17 The Owl Nebula 101
March 18 Space-Walking 101
March 19 XI Ursæ Majoris: the First Computed Binary 102
March 20 The Equinox 103
March 21 The Celestial Equator 104
March 22 The Origin of the Planets 104
March 23 The Hunting Dogs 105
March 24 The Whirlpool 106
March 25 Titan 107
March 26 Messier Objects in Canes Venatici 108
March 27 Monoceros 108
March 28 The Oldest Open Cluster 110
March 29 Miniature Worlds 110
March 30 Nu Hydræ 111
March 31 Van Maanen and the Galaxies 112
April 113
April 1 The April Sky 118
April 2 Leo, the Lion 118
April 3 The Royal Star 119
April 4 Algieba, the Double Star in the Sickle 120
April 5 Features of the Sickle 121
April 6 Denebola: a Fading Star? 122
April 7 R Leonis and the Purkinje Effect 122
April 8 Chort and Zosma: Radial Velocities of Stars 123
April 9 Galaxies in Leo 124
April 10 The Little Lion 125
April 11 Lynx 126
April 12 The Intergalactic Tramp 127
April 13 47 Ursae Majoris: a Planetary Centre? 127
April 14 The Mountains of the Moon 128
April 15 The Spin of the Moon 129
April 16 Méchain and the Nebulæ 130
April 17 Seas at the Moon’s Limb 131
April 18 Constellation Shapes – and the Southern Triangle 131
April 19 The Lunar Surveyors 132
April 20 The Lyrids – and Thatcher’s Comet 133
April 21 Apollo 16 and the Highlands of the Moon 134
April 22 Antlia 134
April 23 The Sextant 135
April 24 The Centaur and the Southern Cross 136
April 25 Features of the Centaur 137
April 26 The Southern Cross 138
April 27 The Jewel Box and the Coal Sack 139
April 28 Lupus 139
April 29 Ara 140
April 30 The Moon and Easter 141
May 143
May 1 The May Sky 148
May 2 Tracing the Zodiac 148
May 3 Areas of the Zodiacal Constellations 149
May 4 The Giant Planet 150
May 5 Meteorites over Britain 151
May 6 The Belts and Spots of Jupiter 151
May 7 The Satellites of Jupiter 152
May 8 Virgo 153
May 9 Spica 154
May 10 Arich 154
May 11 Star Names 155
May 12 A Missing Link? 156
May 13 The Bowl of Virgo 157
May 14 M87: a Giant Radio Galaxy 158
May 15 Minelauva and Stellar Evolution 159
May 16 Nu Virginis: Red Star in the Virgin 159
May 17 May 17 160
May 18 The Legend of Berenice’s Hair 160
May 19 The Coma Cluster 161
May 20 Nebular Objects in Coma 162
May 21 The Sun – from Beta Comæ 162
May 22 Jupiter’s Satellite Family 163
May 23 Corvus 164
May 24 The Antennæ 165
May 25 Crater, the Cup 165
May 26 The Sun – and Richard Carrington 166
May 27 R Hydræ 166
May 28 Lockyer and Stellar Evolution 167
May 29 Der Mond 167
May 30 The Lunar Atmosphere 168
May 31 Occultations of Mars 169
June 171
June 1 The June Sky 176
June 2 Dark Adaptation 176
June 3 The Hale Re.ector 177
June 4 Peculiar Pluto 177
June 5 Pluto and Charon 178
June 6 Boötes, the Herdsman 179
June 7 Arcturus 180
June 8 Transits of Venus 181
June 9 The Ophiuchids 182
June 10 Red Variable: W Boötis 183
June 11 The Vanishing Star 183
June 12 Double Stars in Boötes 184
June 13 Quadrans: the Forgotten Constellation 184
June 14 The Northern Crown 185
June 15 R Coronæ: the Sooty Star 186
June 16 T Coronæ: the Blaze Star 186
June 17 The ‘Leviathan of Parsonstown’ 187
June 18 Scorpius 188
June 19 Antares: the Scorpion’s Heart 189
June 20 Neighbours of Antares 190
June 21 Globular Clusters in Scorpius 190
June 22 The Scorpion’s Head 191
June 23 The Scorpion’s Sting 191
June 24 Open Clusters in Scorpius 192
June 25 Scorpius X-1 192
June 26 Libra 193
June 27 Beta Libræ: a Green Star? 193
June 28 The First Point of Libra 194
June 29 Secchi’s Spectral Classi.cation 195
June 30 Meteorite Craters 195
July 197
July 1 The July Sky 202
July 2 Hercules 202
July 3 Zeta Herculis 204
July 4 Globular Clusters in Hercules 204
July 5 The Changing Moon 205
July 6 Rasalgethi 206
July 7 Telescopic Objects in Hercules 206
July 8 Ophiuchus 207
July 9 Poniatowski’s Bull 208
July 10 Ophiuchus in the Zodiac 209
July 11 Barnard’s Star 209
July 12 Serpens: the Broken Constellation 210
July 13 The Serpens Globular 211
July 14 The Serpent’s Body 211
July 15 The Eagle Nebula 212
July 16 The Central Bay 212
July 17 Sagittarius 213
July 18 Southernmost Sagittarius 214
July 19 The Star-Clouds of Sagittarius 215
July 20 The Centre of the Galaxy 215
July 21 Nebulæ in Sagittarius 216
July 22 Messier 22 217
July 23 The Missing Messier Objects 217
July 24 Corona Australis: the Southern Crown 218
July 25 The Summer Triangle 218
July 26 Lyra 220
July 27 Vega 221
July 28 The Changing Size of the Moon 222
July 29 Beta Lyræ 222
July 30 The Ring Nebula 223
July 31 Epsilon Lyræ, the Double-Double Star 224
August 225
August 1 The August Sky 230
August 2 Neptune: the Outermost Giant 230
August 3 The Perseids – and Comet Swift-Tuttle 231
August 4 Observing Neptune 231
August 5 Aquila 232
August 6 Antinoüs 233
August 7 Altair 233
August 8 Eta Aquilæ 234
August 9 Nova Aquilæ, 1918 235
August 10 The Moon from Orbiter 235
August 11 The Perseid Shower 236
August 12 Meteor Photography 236
August 13 Eros, the Cosmic Lozenge 237
August 14 The Shield and the Wild Duck 238
August 15 R Scuti 238
August 16 Cygnus, the Swan 239
August 17 Deneb: a Celestial Searchlight 240
August 18 The North America Nebula 240
August 19 Albireo, the Coloured Double 241
August 20 P Cygni, the Unstable Star 242
August 21 The ‘Flying Star’ 243
August 22 Variable Stars in Cygnus 243
August 23 Clusters in Cygnus 244
August 24 Uranus 245
August 25 Giants from Close Range 246
August 26 Rings and Moons 246
August 27 The Migrating Star 247
August 28 Mars at its Nearest 248
August 29 Mars through the Telescope 249
August 30 Observing Mars 250
August 31 Close-Range Views of Mars 250
September 253
September 1 The September Sky 258
September 2 The First Four Asteroids 258
September 3 The Martian Scene 259
September 4 The Legend of the Dolphin 260
September 5 Doubles and Variables in Delphinus 261
September 6 The Delphinus Globulars 262
September 7 Equuleus 262
September 8 Sagitta, the Arrow 263
September 9 Vulpecula 263
September 10 The Sea of Tranquillity 264
September 11 Tracing the Zodiac: Continued 265
September 12 The Sea-Goat 265
September 13 The Flight of Luna 2 1959: Landing of Luna 2 on 266
September 14 Beta and Alpha Capricorni 267
September 15 Messier 30 268
September 16 Pegasus 268
September 17 The Light-curve of Beta Pegasi 269
September 18 Epsilon Pegasi: a Suspected Variable 270
September 19 Double Star Separations 270
September 20 The Planet of 51 Pegasi? 272
September 21 Remote Objects in Pegasus 272
September 22 Equal Day and Night 273
September 23 Aquarius, the Water-Bearer 274
September 24 Zeta Aquarii 275
September 25 Harvest Moon 275
September 26 Blue Moons 276
September 27 Messier Objects in Aquarius 277
September 28 The Saturn Nebula and the Helix 278
September 29 Pisces 278
September 30 TX Piscium and Van Maanen’s Star 279
October 281
October 1 The October Sky 286
October 2 The Southern Fish 286
October 3 Sculptor 288
October 4 The Start of the Space Age 288
October 5 Cetus 289
October 6 The ‘Wonderful Star’ 290
October 7 Tau Ceti: a Near Neighbour 291
October 8 Giants and Dwarfs of the Sky 292
October 9 Flare Stars 293
October 10 The Draconid Meteors 293
October 11 Objects in Cetus 294
October 12 The Chemical Furnace 295
October 13 Crater Linné 295
October 14 William Lassell and hisTelescope 296
October 15 Draco, the Dragon 297
October 16 Nearby Stars in Draco 298
October 17 The Old Pole Star 298
October 18 The Moving Pole 299
October 19 Gamma Draconis and Aberration 300
October 20 Andromeda 301
October 21 The Orionids – and Halley’s Comet 302
October 22 The Great Spiral 303
October 23 Spörer and his Law 303
October 24 The Distance of M31 304
October 25 The Other Side of the Moon 305
October 26 The Form of M31 305
October 27 The Other Side of the Moon 306
October 28 Companions of the Andromeda Spiral 307
October 29 Aries, the Ram 307
October 30 Triangulum 308
October 31 The Pinwheel Galaxy 309
November 311
November 1 The November Sky 316
November 2 Eridanus, the River 316
November 3 The Taurids 318
November 4 The South Celestial Pole 318
November 5 The Clouds of Magellan 320
November 6 Venus in the Morning Sky 320
November 7 The Rotation of Venus 321
November 8 Venus: the Phantom Satellite 322
November 9 The Ptolemæus Chain 322
November 10 Conditions on Venus 323
November 11 Perseus and the Sea-Monster 324
November 12 The Demon Star 325
November 13 The Light-curve of Algol 326
November 14 The Sword-Handle in Perseus 326
November 15 Objects in Perseus 327
November 16 Tracing the Equator 327
November 17 Leonid Night 328
November 18 Canopus 328
November 19 The Andromedid Meteors 330
November 20 Hubble and the Galaxies 330
November 21 Auriga, the Charioteer 331
November 22 Capella 332
November 23 The Mysterious ‘Kid’ 333
November 24 Zeta Aurigæ 333
November 25 Clusters in Auriga 334
November 26 The Celestial Crane 334
November 27 Phœnix 336
November 28 Peacock and Indian 337
November 29 Tucana 338
November 30 The Brightest Lunar Crater 339
December 341
December 1 The December Sky 346
December 2 The Colours of the Stars 346
December 3 Stars of Many Kinds 347
December 4 Some Red or Orange Stars 348
December 5 Twinkling Planets? 348
December 6 Sizes of the Constellations 349
December 7 Space Pioneer 349
December 8 Occultation Series 350
December 9 Pluto: Planet or Not? 350
December 10 Taurus 351
December 11 The Hyades 352
December 12 The Seven Sisters 352
December 13 The Geminids 353
December 14 The Stars of the Pleiades 354
December 15 Lambda Tauri 354
December 16 The Crab Nebula 355
December 17 The Ringed Planet 356
December 18 The Rings of Saturn 356
December 19 Storms on Saturn 357
December 20 Space-craft to Saturn 358
December 21 The Satellites of Saturn 358
December 22 The Cassini Mission 359
December 23 The Ursids – and Tuttle’s Comet 359
December 24 The Barwell Meteorite 360
December 25 The Star of Bethlehem 361
December 26 The False Cross 362
December 27 Eta Carinæ 363
December 28 Beta Pictoris: a Planetary Centre? 364
December 29 Keeping Watch on the Sun 364
December 30 A Last Look Round 365
December 31 The End of the Century 365
The 88 Constellations 367
Glossary 369
The Greek Alphabet 379
Index 381

August (p. 214-215)

August 1
The August Sky

For the northern observer, the nights are lengthening. The Summer Triangle continues to dominate the scene, while the main autumn constellation, Pegasus, makes its entry in midevening. The Great Bear is rather low in the north-west, which means that the W of Cassiopeia is high in the northeast. Arcturus is setting, and Capella is so low over the northern horizon that any mist or light pollution will conceal it. We have lost the Scorpion, though Sagittarius remains on view very low in the south. In the early hours of the morning, the lovely star-cluster of the Pleiades appears in the east. By the end of August it rises well before midnight – a reminder that the hot days are over, and winter, with its frosts and fogs, lies ahead.

Remember that August is the ‘meteor month’. The Perseids, which peak on 12 August, may always be relied upon to give good displays, and even in the presence of the Moon quite a number of ‘shooting-stars’ can always be expected. The shower has already started at the beginning of the month, and goes on until near the end of the third week. From the southern hemisphere, the Vega-Deneb-Altair triangle is visible in the east, though only Altair is reasonably high from Australia or South Africa. Scorpius and Sagittarius remain prominent, though Scorpius is sinking in the west.

The Southern Cross is low, and so is Canopus, with the Southern Fish high up, and Pegasus appearing in the northeast. Of course the Perseids can be seen, but the radiant lies far in the north, so that for once Britons have the advantage over Australians. The Clouds of Magellan are gaining altitude, and this is a good time to pick out the admittedly rather confusing Southern Birds – Grus, Pavo, Phœnix and Tucana.


August 2
Neptune: the Outermost Giant

Throughout the period we are covering here, Neptune reaches opposition in the late northern summer – from 8 August in 2005 to 19 August in 2010; the synodic period is only 367.5 days. Throughout the period Neptune remains in Capricornus, around declination –19°; at the 2002 opposition it remains near the star Rho Capricorni, magnitude 4.8. Neptune’s mean opposition magnitude is 7.7.

This means that it is well below naked-eye visibility, but binoculars will show it in the guise of a starlike point. Telescopically it appears as a small, bluish disk, with an apparent diameter of around 2 seconds of arc. Ordinary telescopes will show no surface features, though markings have been recorded very distinctly from the Hubble Space Telescope – and of course from the one space-craft to have passed by it, Voyager 2 in 1989. There are 11 known satellites, of which 6 were found during and after the Voyager 2 encounter. Of the two attendants previously known, Triton is an easy telescopic object with adequate equipment, but Nereid is very faint indeed, and the recently-found satellites are beyond the range of Earth-based instruments.