In this lecture we discuss the geocentric model of Ptolemy, the heliocentric model of Aristarchus and how Hipparchus tested it using the concept of parallax.  We also saw how to use observations of parallax to measure the distance to celestial objects.

ASTR209 - Lecture 4

This page contains live, video podcasts of Astronomy 209 (Introduction to Astronomy II - The Cosmos) lectures taught at the University of Calgary.  AST209 is a comprehensive, descriptive overview of various aspects of the universe outside the solar system covering topics such as: the history of astronomy, interstellar space, stars, galaxies, black holes, supernovae, and the origins of life and the universe.   Course details can be found at the AST209 Course website.

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In this lecture we continue to discuss the process of star formation from the fragmentation of a giant molecular cloud, to the collapse of the fragment and the formation of the protostar and disk.  We also show where the protostar appears on the HR diagram, and how it evolves onto the main sequence.

ASTR209 - Lecture 19

In this lecture we discuss the basic properties of stars and the stellar Classification system (OBAFGKM) as well as luminosity classes (I through V).  We also investigate the  the HR diagram and what it infers about stellar properties.

ASTR209 - Lecture 15

In this lecture (back from illness, reading week, and the midterm exam!) we talk about "seeing", different telescopes, why we go to high altitudes to build them, and why we build telescopes to operate at different wavelengths (i.e. what different physical phenomena in the Universe emit at different wavelengths).  We also begin to talk about radio telescopes.

ASTR209 - Lecture 12

No podcasts of these lectures due to illness

ASTR209 - Lectures 10 & 11

In this lecture we explore the many uses of Newton's version of Kepler's law as a tool to determine the masses of objects in the Universe.  We then move on to Part 2 of the class notes (the Electromagnetic spectrum) and talk about the particle and wave natures of light including concepts of diffraction, interference, wavelength, frequency and energy.

ASTR209 - Lecture 4

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