Helix nebula in IR (Vista)
Mars weather (MRO)
Titan above Saturn's rings (Cassini)
Ligeia Mare on Titan (Cassini)
Jupiter (Juno)
Nightscape (Mark Gee)
Flyby Pluto (New Horizons)
Jupiter (Juno)
Neptune's moon Triton (Voyager 2)
Earth and Moon from Saturn (Cassini)
Aurora on Saturn (Cassini)
Sombrero galaxy (HST)
Earth setting on Moon (Kaguya)
Saturn closeup (Cassini)
Sunset on Mars (Spirit rover)
Eta Carinae (Stephen Chadwick)
Crater slope on Mars (MRO)
Jupiter and Ganymede (HST)
Pluto topography (New Horizons)
Titan and ring shadow (Cassini)
Carina Nebula (HST)
Victoria crater on Mars (Erik Wernquist)
Pluto mountains and plains (New Horizons)
Vela supernova remnant (Stephen Chadwick)
Geysers on Enceladus (Cassini)
Andromeda galaxy (Robert Gendler)
The Nile at night (ISS)
Saturn's moon Enceladus (Cassini)
Saturn's moon Epimetheus (Cassini)
Rhea in front of Titan (Cassini)
Horsehead nebula (HST)
Saturn's moon Hyperion (Cassini)
Occam crater on Ceres (Dawn)
Carina Nebula in IR (HST)

Our Lectures

are typically used to give presentations, although they can also be used for self study.
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Most of the Slide shows are accompanied by a narrative text file and/or handout(s) (in pdf-format) that can be downloaded and which contain background information. These attachments should be studied beforehand by the presenter for the best results or can be used as a study resource for self study. These documents can be downloaded from the "Resources" tab (top left) in each presentation.

Open any one of the categories below and click on the icon in the column "Run" (only visible when you are logged in) to open the show in a separate tab. Make sure to scroll down to see all our presentations.

Available Lecture Series

 Individual Presentations

Click on icon in column Run The Slide presentation will open in a separate tab
Introduction to Astronomy History, Solar System, Search for Life, Milky Way, Life Cycle of Stars, Deep Space.  
Kepler's Laws Describing planetary motion, history, kepler's laws, newton's gravitation, modern space travel.  
Leap Seconds; Why? Strong antidote to a general misconception.  
Lunar Eclipse 2018 About the "Super-Blood" Moon on 1 February 2018  
Solar Eclipse 2019 About the Solar Eclipse on 2 July 2019 as seen from the La Silla observatory in Chile, Paranal observatory and more...  

The Rhythmic Sky Course

In this course we discuss how we see celestial objects move in the sky and why this happens that way.
Version 5.

Title Description Run
Click on icon in column Run The Slide presentation will open in a separate tab
The Rotating Earth 24 hours defined as one revolution, causing night and day. Direction of rotation. East and West. Clockwise and counter clockwise. Sun as seen from N and S hemisphere. Midday sun (noon). Modern Time system and Time zones. Motion of the stars. Celestial poles and Latitude. Circumpolar and rising and setting stars. Earth as a natural clock. Variations in LOD. Measurements and explanation. Atomic clocks and UTC, Leap seconds. Secular slowing of Earth rotation. Time zones and Daylight saving time.  
The Orbiting Earth Heliocentric model. Annual orbit around Sun. Direction and speed as compared with other planets. Sidereal and Solar day. Seasons, ecliptic and axial tilt. Declination of the Sun. Arctic circles and Tropics, Equinoxes and Solstices. Sun angles. Elliptic orbit of the Earth. Equation of time. Calendar and leap years. Celestial navigation.  
The Moon Orbit and movement. Moon phases. Lunar cycle and Daily movement. Angular size and distance. Orbital plane of the Moon. Tidal locking. Near side and far side. Lunar topography. Synodic cycle. Lunar calendar and life on Earth. Lunar and Solar Eclipse. Elliptic orbit and libration.  
The Planets Wandering stars. Dance of the planets and retrograde motion. Phases and distances. Visibility, naked eye and telescope. Transits of inner planets. Use of Orrery software. Mythology of planets and other bodies. Visible Moons of other planets. Minor planets and asteroids. Kepler Orbital motion, History and significance. Periods of the planets. Seasonal Ecliptic.  
What else moves in the sky & aspects of Stargazing The Milky Way in the sky. Magellanic Clouds and other objects. Constellations. Star names. Stars in constellations. N and S hemisphere views. Magnitude and brightness. Atmospheric effects. Planetarium software and Apps.  

Exploring the Solar System Course

In this course we travel virtually through our Solar System, visiting planets, and many moons, minor planets, asteroids, and comets. 
Version 5.

Click on icon in column Run The Slide presentation will open in a separate tab
What System? What is systematic in our Solar System? What are Orbits: debunking misconceptions. A sense of Scale and Emptiness.  
Formation and Evolution How the Sun formed. How did it all come about? Formation Theory of the Solar System. Future of the Sun. Future of planet Earth.  
The Sun Early science. Life Cycle. Mass and Rotation. Structure. Solar activity. Solar Cycle. Space missions.  
Nuclear Fusion in Stars The powerhouse of the Universe. The basic principles of nuclear Fusion explained. How we are trying to do the same on Earth.  
The Planets Size and Scale. Orbits and Rotation. Rocky planets and their properties. Gas planets and their properties. Short overview of each planet individually.  
Mars in Depth - In Space Orbit; Rotation and Seasons; How to travel to Mars - Transfer Orbit, Launch Window; Entry, Descent and Landing; History of Exploration  
Mars in Depth - Closeup Atmosphere; Wind and Dust; Gravity; Radiation; Topography; Areological History; History of Water and where it is now.  
Mars in Depth - Science How it started with Viking; Climate Cycles; Early Mars' Atmosphere; Where is all the CO2? Magnetic Field.  
Mars in Depth - Exploring All the missions - Summary; Operational missions; Exploring from Orbit; Exploring at the Surface; Future Exploration.  
Jupiter History of Exploration. Galileo and Juno missions in detail.  
Moons of the Solar System Overview of the many moons in the Solar System. Discussion of several of the larger moons in detail.  
Small Worlds Part 1 Definitions and Classification.  Importance of the small worlds. Inner Solar System. Near Earth Objects and Hazards. Meteoroids, Meteors and Meteorites. Main Asteroid Belt.  Previous, current and proposed missions to asteroids and results.  
Small Worlds Part 2 Outer Solar System. Trans Neptunians and Kuiper Belt. Pluto and its companions. New Horizons mission. Planet Nine. Comets and the Oort Cloud. Previous and current missions to comets with results. Interstellar visitors.  
Search for Life What is Life? Building blocks of Life. Environments for Life. How to define Alien Life? What have we found on Mars, Europa, Enceladus, Titan? Where should we go next. Planetary Protection.  

Leaving the Solar System Course

In this course we leave our Solar System and explore up to about 7000 light years around the Sun. We discuss major observation techniques and look at different types of stars and other objects that we find and their properties. 
Version 5.

Click on icon in column Run The Slide presentation will open in a separate tab  
Sense of Scale Continuing our scale model up to about 7000 light years. What do we find and what can we see with the naked eye? Units of distance in Astronomy; the magnitude scale.  
Multiple systems Most stars are not alone. Binaries, Trinaries, etc. Open Clusters.  
Distance and proper Motion Parallax as the first rung of the cosmic distance ladder outside the Solar System. How does it work and how do we separate it from proper motion of stars?  
Exploring the Nearest stars An extensive exploration at increasing distance of a selection of the star systems, Open Clusters and Nebulae we find in this region.  
About Stars Introduction to the most important physical characteristics of a star. Mass; what is luminosity?; Relation between temperature and colour. Introducing the Hertzsprung-Russell (HR-) diagram.This prepares for Spectroscopy and Stellar Evolution.  
Nature of Light What is light? From Pythagoras to Niels Bohr. Reflection, Refraction, Diffraction and Interference. Wave-Particle Duality? Quantum model of light. Electron energy levels. Photon energy and absorption and emission lines in the light spectrum.  
Spectroscopy in Astronomy Spectroscopy as the most important observation technique in astronomy. Discovery of Fraunhofer lines. Spectral classification and the HR-diagram again. Applications of spectroscopy. Radial velocity.  
Stellar Evolution Star formation. Nuclear fusion explained. Main sequence stars. The final stage for sun-like and more massive stars. Neutron stars and Black holes. Mapping stellar evolution on the HR-diagram. The importance of the HR-diagram.  
Exoplanets How do we find exoplanets? Observation programmes in space and on the ground, Properties and classification of exoplanets. How do we search for life? Any chance of finding intelligent life?  
Travel to the stars A popular topic around the coffee table, but how realistic is that?. An inventory using a bit of physics.  

Exploring the Milky Way Course

In this course we travel up to about 500,000 light years and explore our home galaxy in detail.
Version 5.

Click on icon in column Run The Slide presentation will open in a separate tab  
Sense of Scale & the Milky Way in the Sky Continuing our scale model up to about 500,000 light years. The basics of the Milky Way galaxy. How do we see it and how does it move in the sky?  
Finding Structure History of how we learned about our galaxy.  
Galactic Distance Cosmic distance ladder continued. Main Sequence Fitting, Luminosity and Distance, Cepheids and RR Lyrae.  
Beyond the Visible Overview Multi-wavelength astronomy. Radio including VLBI, Infrared, Visible light, Ultraviolet, X-ray and Gamma-ray. History and Detection technology.  
Multi-wavelength Milky Way Observation techniques beyond the visible light and how that changed our view of the galaxy.  
Structure of the Milky Way How we have learned about the galactic structure in detail. Latest results and questions.  
Towards the Centre The bulge, long bar and the very dynamic centre of our galaxy. Latest observations.  
Special Relativity Low-level-mathematical but comprehensive introduction to Galilean and Special Relativity.  
General Relativity Low-level-mathematical but comprehensive introduction to General relativity. This is also a preparation for Cosmology in the course Going Deep.  
Black Holes History of our developing knowledge about Black Holes in general, what we know about our own Supermassive Black Hole. We also briefly review the recent imaging of the Supermassive Black Hole in galaxy M87 by the Event Horizon Telescope consortium.  
Dynamics of the Milky Way & Dark Matter How do we move in space; density waves in spiral arms; galaxy rotation and mass; rotation curve mystery and Dark Matter.  
Dwarf Galaxies and Streams Dwarf galaxies around the Milky Way, their dynamics and importance for the study of Dark Matter.  

Going Deep Course

In this course we travel all the way out to the edge of the observable Universe.
Version 4.

Click on icon in column Run The Slide presentation will open in a separate tab  
A Sense of Scale Island Universes, Measuring distance, Space & Time; Telescopes as time machines; What can we know?  
Exploring the Deep From our nearest neighbour the Andromeda galaxy all the way to the edge; Groups, Clusters, Superclusters, Filaments, Walls and Voids. The observable Universe.  
Deep Sky Surveys How do we know this structure? The major Deep Sky Surveys or Redshift Surveys and instrumentation. Evidence for Dark Matter in deep space. Computer simulations to understand the large scale structure of the Universe.  
About Galaxies Galaxy classification: Hubble sequence and modern classification. Galaxy evolution. Galaxy formation in the early Universe. Computer simulations of galaxy interactions.  
The Expanding Universe Discovery of and Imagining expansion, understanding Hubble's Law, Cosmological redshift, modern research, current status of the Hubble parameter.  
Distance in an Expanding Universe Cosmological redshift and a cosmological model, what is distance in an expanding Universe? Working with cosmological redshift, independent distance techniques, the observable Universe.  
Big Bang Cosmology Brief history. General Relativity as the foundation. Cosmological Principle, Friedmann, Lemaître, Robertson, Walker. Energy density and Critical density. The makeup of the Universe.  
Cosmic Microwave Background Discovery, origin of the CMB, observations, significance for cosmology.  
Observational Cosmology Discovery of acceleration, standard candles and standard rulers, type Ia Supernovae, using the CMB, benchmark model, Big Bang nucleosynthesis, cosmic history from very early Universe until ultimate fate.  
The Mysterious Universe First mysteries: flatness, horizon and magnetic monopole problems. A solution: Inflation?. Antimatter problem. Discrepancy in H0. Dark Matter, Dark Energy. Planned new observations. Epilogue to the course.  

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