00057 - Astronomy

Course Unit Page


This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Quality education

Academic Year 2021/2022

Learning outcomes

The aim of the course is to provide the fundamental knowledge of the Earth, the Solar System, the Stars and the Galaxy, as well as the indispensable notions to describe the orbital motions (the two-body problem) and the astronomical observations, such as the determination of the position of cosmic objects, their distance and the measurement of the emitted radiation.

Course contents


- Fundamentals of spherical trigonometry. Astronomical coordinate systems. Apparent motions of celestial bodies. Perturbations of coordinates. Time and its measurement. Constellations.
- The motion of celestial bodies. The two-body problem. Kepler's laws. Introduction to the N-body problem.
- The Earth. Climatic zones, seasons, eclipses. Tidal forces.
- The Solar System. The Moon. The motion of planets. Inner planets. Outer planets. Minor bodies. Origin of Solar System.
- Radiation from astronomical objects. Definitions. Luminosity. Flux. Surface brightness. Spectra. Apparent and absolute magnitudes. Color indices. Extinction.
- Introduction to the black body radiation. Planck's law. Wien's law. Stefan-Boltzmann' s law.
- Introduction to atomic processes. Atomic structure. Electronic transitions. Spectral lines. Outline of thermodynamics.
- The spectral classification of stars. The Hertzsprung-Russell diagram.
- The Sun. Structure. Outline of production and transfer of energy. Influence of the Sun on Earth.
- Binary stars. Classification. Mass estimate. The mass - luminosity relation.
- The evolutionary meaning of the H-R diagram.
- Variable stars.
- Stellar clusters and populations.
- Extrasolar planets: discovery methods and observed properties.
- Our Galaxy. Structure and components. Rotation curve. Dark matter.
- The cosmic distance ladder.


A module of the course is dedicated to practical exercises where the students apply the methods learned during the lectures to problems aimed at estimating astronomical distances and the properties of astrophysical objects.


Karttunen H. et al., "Fundamental Astronomy", Springer Verlag.


1. Introduction 1.1 The Role of Astronomy. 1.2 Astronomical Objects of Research. 1.3 The Scale of the Universe . 2. Spherical Astronomy. 2.1 Spherical Trigonometry (CENNI). 2.2 The Earth. 2.3 The Celestial Sphere. 2.4 The Horizontal System. 2.5 The Equatorial System. 2.7 The Ecliptic System. 2.8 The Galactic Coordinates. 2.9 Perturbations of Coordinates. 2.10 Positional Astronomy. 2.11 Constellations. 2.12 Star Catalogues and Maps. 2.13 Sidereal and Solar Time. 2.14 Astronomical Time Systems. 2.15 Calendars (NO Reduction of coordinates). 4. Photometric Concepts and Magnitudes. 4.1 Intensity, Flux Density and Luminosity. 4.2 Apparent Magnitudes. 4.3 Magnitude Systems. 4.4 Absolute Magnitudes. 4.5 Extinction and Optical Thickness. 5. Radiation Mechanisms 5.1 Radiation of Atoms and Molecules. 5.2 The Hydrogen Atom. 5.4 Quantum Numbers, Selection Rules, Population Numbers. 5.6 Continuous Spectra. 5.7 Blackbody Radiation. 5.8 Temperatures. 6. Celestial Mechanics. 6.1 Equations of Motion (dispensa). 6.2 Solution of the Equation of Motion (dispensa). 6.3 Equation of the Orbit and Kepler’s First Law (dispensa). 6.4 Orbital Elements CENNI. 6.5 Kepler’s Second and Third Law (vedere dispensa). 6.6 Systems of Several Bodies CENNI. 6.9 Escape Velocity (dispensa). 6.11 The Jeans Limit (dimostrazione in slide). 7. The Solar System. 7.1 Planetary Configurations. 7.2 Orbit of the Earth and Visibility of the Sun. 7.3 The Orbit of the Moon (Tides: dispensa). 7.4 Eclipses and Occultations. 7.5 The Structure and Surfaces of Planets. 7.6 Atmospheres and Magnetospheres. 7.7 Albedos (CENNI). 7.9 Thermal Radiation of the Planets. 7.10 Mercury. 7.11 Venus. 7.12 The Earth and the Moon. 7.13 Mars. 7.14 Jupiter. 7.15 Saturn. 7.16 Uranus and Neptune. 7.17 Minor Bodies of the Solar System. 7.18 Origin of the Solar System. 8. Stellar Spectra. 8.1 Measuring Spectra. 8.2 The Harvard Spectral Classification. 8.3 The Yerkes Spectral Classification. 8.4 Peculiar Spectra. 8.5 The Hertzsprung--Russell Diagram. 8.6 Model Atmospheres (CENNI). 8.7 What Do the Observations Tell Us? 9. Binary Stars and Stellar Masses. 9.1 Visual Binaries. 9.2 Astrometric Binary Stars. 9.3 Spectroscopic Binaries. 9.4 Photometric Binary Stars. 12. The Sun. 12.1 Internal Structure. 12.2 The Atmosphere. 12.3 Solar Activity. 13. Variable Stars. 13.1 Classification. 13.2 Pulsating Variables. 13.3 Eruptive Variables. 16. Star Clusters and Associations. 16.1 Associations. 16.2 Open Star Clusters. 16.3 Globular Star Clusters. 17. The Milky Way. 17.1 Methods of Distance Measurement. 17.3 The Rotation of the Milky Way. 17.4 Structural Components of the Milky Way. 17.5 The Formation and Evolution of the Milky Way.

WARNING: the slides shown during the course will be made available through the AMS Campus and can be used as a guide to the level of detail required for each subject as well as as an integration in cases where the text is not enough (e.g. extrasolar planets).

Teaching methods

The lectures are oral and make use of both slides (as a visual help) and traditional blackboard for the proofs, examples and exercies.

Assessment methods

The exams are oral (also for the excercises module). During the exams, at least three questions are asked in order to verify the learning level and the ability of the student to link coherently the different topics of the course and of the module excercises. 

Teaching tools

Traditional blackboard. Projector for computer presentations.

Office hours

See the website of Andrea Cimatti

See the website of Michele Ennio Maria Moresco