1 Galaxies: an overview
1.1 Introduction 1
1.2 A brief history of galactic astronomy 2
Photometric models of the Milky Way 5
The nature of the spiral nebulae 10
Kinematic models of the Milky Way 15
Stellar populations 20
More recent developments 21

2 Astronomical Measurements
2.1 Positions, motions and coordinate systems 27
The equatorial system 27
Galactic coordinates 30
Parallax 31
Proper motions 34
Precession and nutation 35
Astrometric systems 37
2.2 Distances determined from velocities 38
Radial velocities 39
Distances from the movingcluster method 40
Secular parallaxes 42
Statistical parallaxes 45
2.3 Magnitudes and colors 46
Apparent magnitudes 47
Colors 52
Absolute magnitudes 56
Absolute energy distributions
and bolometric magnitudes 58
Mass-to-light ratios 60
Surface brightness and isophotal radii 61
2.4 Gravitational lensing 62
2.5 Archival data and catalogs 67
On-line resources 71
Problems 74

3 The Properties of Stars
3.1 The masses of stars 76
The Mass of the Sun 77
Masses of binary stars 78
Visual binaries 78
Spectroscopic binaries 79
3.2 The radii of stars 82
Phase interferometry 82
Intensity interferometry 83
Speckle interferometry 83
Lunar occultations 84
Eclipsing binaries 84
Astrophysical estimates 86
3.3 Classification of stars 87
Novae 87
Pulsars 87
Classification of stellar spectra 88
The MK system 90
3.4 Physical interpretation of stellar spectra 94
3.5 Color-magnitude diagrams 102
Observed CM-diagrams 103
Luminosity and color as functions of spectral class 104
The physical properties of stars on the MS and RGB 109
3.6 The stellar luminosity function 109
Malmquist bias 111
Lutz-Kelker Bias 115
The general luminosity function 119
Cluster luminosity functions 119
Photometrically complete surveys 119
Proper-motion selected surveys 120
The luminosity function of a given MK spectral class 127
Catalogs of the nearby stars 130
3.7 Interstellar dust 131
Extinction and reddening 133
Reddening-free indices 138
Polarization of starlight by dust 140
Extinction of sightlines out of the Galaxy 140
Problems 143

4 Morphology of Galaxies
4.1 Morphological classification of galaxies 146
The Hubble sequence 149
Effects of environment 157
The galaxy luminosity function 162
The field galaxy luminosity function 162
The cluster galaxy luminosity function 165
The luminosity function divided by morphological type 167
The Local Group 169
4.2 Surface Photometry of Galaxies 172
The night sky 173
Effect of seeing 176
Deprojecting galaxy images 179
4.3 Photometry of Elliptical Galaxies 185
Radial surface-brightness profiles of elliptical galaxies 185
cD galaxies 186
Dwarf elliptical galaxies 190
Centers of elliptical galaxies 191
Color and line-strength gradients in elliptical galaxies 193
Shapes of elliptical galaxies 194
Ellipticity 194
Deviations from ellipses 199
Fine structure 201
Correlations among global parameters of elliptical galaxies 204
The Dn - [Sigma]<0 correlation 209
Dwarf elliptical galaxies 209
4.4 Photometry of Disk Galaxies 210
Photometric effects of dust 211
Overall shapes of disk galaxies 212
Bulge-disk decomposition 214
Shapes of bulges 222
Color and metallicity gradients in disk galaxies 223
Spiral structure in disk galaxies 224
Barred galaxies 228
Vertical structure of bars 231
Rings in SB galaxies 233
Dust lanes in SB galaxies 234
Lop-sidedness in SB galaxies 234
4.5 Globular cluster systems 235
Globular cluster luminosity function 236
Specific frequency of globular clusters 237
Radial density profiles and shapes 238
Color distributions 239
4.6 Abnormal galaxies 241
Starbursting systems 241
Systems with active galactic nuclei 244
Host galaxies of AGN 250
The unified model of AGN 251
Problems 255

5 Evolution of Stars and Stellar Populations
5.1 Stellar evolution and the CM diagram 259
Placing models in the CM diagram 262
Features in the CM diagram 263
Characteristic initial masses 267
Bounding curves in the CM diagram 274
Dependence of CM diagrams upon metallicity 276
The cosmic helium abundance 279
Simple numerical relations 279
Star formation 281
The initial mass function 283
Pulsating stars 287
Classical Cepheid variables 289
Mira variables 292
W Virginis stars 293
RR Lyrae stars 293
5.2 Synthesis of the chemical elements 296
Basic nuclear physics 296
Metal production at Mi < Mup 301
Supernovae 302
Metal production by core-collapse supernovae 303
Metal production by type Ia supernovae 305
5.3 Models of chemical enrichment 306
The closed-box model 306
The leaky-box model 308
The accreting-box model 313
5.4 Evolution of stellar populations 314
Analytical results 315
Numerical models of population evolution 317
Problems 324

6 Star clusters
6.1 Globular clusters 327
Globular cluster stellar photometry 332
Color-magnitude diagrams 334
The main sequence and subgiant branch 335
The horizontal branch 337
Comparison with Theoretical CM diagrams 339
Globular cluster ages 344
Turnoff point ages 344
Isochrone fitting 345
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