Small and large telescopes are being installed all around the world. Astronomers have thus acquired better access to more modern equipment; not in the least to photometers, which are very important tools for the contemporary observer. This development of higher quality and more sensitive equipment makes it very necessary to improve the accuracy of the measurements. This guide helps the astronomer and astronomy student to improve the quality of their photometric measurements and to extract a maximum of information from their observations.
The book is based on the authors' observing experience, spending numerious nights behind various instruments at many different observatories.

1 Introduction.- 1.1 The quantum nature of light.- 1.2 Photometric concepts and radiometric quantities.- 1.3 Natural sources of diffuse illumination.- 1.4 Detectors.- 1.5 The most versatile detector of light images.- 1.6 Ancient catalogues.- 1.7 Definition of the magnitude scale.- 1.8 The perception of colors.- 1.9 Colors and visual observations.- 1.10 Major sources of errors in ancient visual observations.- 1.11 Magnitude.- 1.12 Magnitude systems.- 1.13 Bolometric magnitude.- 1.14 Apparent and absolute magnitudes.- 1.15 Color index.- 1.16 Characteristics of the photometric response curve.- 2 The telescope.- 2.1 Types.- 2.2 Requirements and specifications.- 3 Photoelectric photometers.- 3.1 Types of photoelectric photometers.- 3.2 The sequential photometer.- 3.3 The simultaneous photometer.- 3.4 The multi-star photometer.- 4 The photomultiplier.- 4.1 The photoelectric effect.- 4.2 Types of photomultipliers.- 4.3 The essential parts of a photomultiplier tube.- 4.4 Anode current and its measurement.- 4.5 Characteristics of photomultipliers.- 5 Photometric filters.- 5.1 Fundamental characteristics.- 5.2 Gelatin filters.- 5.3 Glass filters.- 5.4 Interference filters.- 5.5 Custom-design filters.- 5.6 Image-quality filters.- 5.7 Neutral-density filters.- 5.8 Circular variable filters.- 6 Atmospheric extinction.- 6.1 Absorption, scattering and dispersion of light.- 6.2 Monochromatic extinction.- 6.3 Definition of the air mass.- 6.4 Calculation of the air mass.- 6.5 Heterochromatic extinction.- 6.6 Conclusions.- 7 Atmospheric turbulence: scintillation and seeing.- 7.1 Scintillation.- 7.2 Seeing.- 8 Color transformation.- 8.1 Introduction.- 8.2 Narrow-band photometry.- 8.3 The general color-transformation problem.- 9 Interstellar extinction.- 9.1 Monochromatic extinction.- 9.2 Wide-band extinction.- 10 Principles of data analysis.- 10.1 Introduction.- 10.2 Monochromatic photometry.- 10.3 Multifilter photometry.- 10.4 General remarks.- 10.5 Examples of reduction algorithms.- 11 Homogenization.- 11.1 Introduction.- 11.2 Conformity.- 11.3 Homogenization.- 11.4 Merging data from a single system.- 11.5 Conclusions.- 12 Infrared photometry.- 12.1 Introduction.- 12.2 Chopping and nodding.- 12.3 The detector.- 12.4 The photometer.- 12.5 Observation and reduction of infrared data.- 12.6 Day-time observing.- 13 Charge-coupled devices.- 13.1 Introduction.- 13.2 The detector.- 13.3 The camera.- 13.4 Characteristics of CCDs.- 13.5 Extraction of data from a frame.- 13.6 Aperture photometry.- 13.7 Profile fitting.- 13.8 Extinction.- 13.9 Color transformation.- 14 Photographic photometry.- 14.1 Introduction.- 14.2 The photographic emulsion as a storage medium.- 14.3 The characteristic curve.- 14.4 Post-observational processing of plates and films.- 14.5 Calibration of digitally recorded photographic densities.- 14.6 Photometric analysis of photographic intensities.- 15 The observations.- 15.1 Introduction.- 15.2 Preparing the observing run.- 15.3 Programme scheduling.- 15.4 Evaluation of the quality of the signal for non-imaging detectors.- 15.5 Noise and error on sky background.- 15.6 Some practical hints.- 16 Photometric systems.- 16.1 Introduction.- 16.2 The visual system.- 16.3 Photographic systems.- 16.4 Photoelectric systems.- 16.5 Absolute calibration.- Appendix A. References.- Appendix B. Glossary.- Appendix C. Symbols and notations.- Appendix D. Index.