Digital Movie Gallery

These digital movies were used to illustrate concepts discussed in my Astronomy 161 lectures. At present, these are all experimental, and your feedback would be greatly appreciated.

The movies are all currently in the popular QuickTime format. QT viewer plug-ins are readily available for the most popular PC and Mac browsers (Netscape and Internet Explorer). MPEG players seem to be much less common, and we have not yet found one that suits our needs.

All of the Solar System animations (except as noted) were generated using Starry Night (Deluxe v2.1 and Pro v3.0.x and 3.1.1). Some further editing was done using QuickTime 4 Pro on a PII/350 PC computer.


Copyright Notice

All data files are Copyright Richard W. Pogge, The Ohio State University. All Rights Reserved.


Index of Movies

Daily (Diurnal) Motions of Stars
Circumpolar Stars from Columbus, Ohio
The Sun's Path along the Ecliptic through the Zodiac
Moon Phases & Earth Phases over 1 Lunar Month
2024 April 8 Total Solar Eclipse
Mars Retrograde Motion during 1994/95
Ptolemaic Perspective on the Solar System (150 AD)
Ptolemaic & Copernican Perspectives on the Solar System (1543-1550 AD)
The Solar System Movie

Daily (Diurnal) Motions of Stars

These three movies show the daily paths of stars as seen looking East from three different locations on the Earth:
Equator (Quito Ecuador): 1.9Mb QuickTime Movie
Columbus, Ohio (40 N):1.9Mb QuickTime Movie
North Pole (90 N):1.9Mb QuickTime Movie

These movies illustrate how the apparent daily paths of stars and the moon differ when viewed from three different latitudes on the Earth: the Equator, Latitude 40 N, and the North Pole. The movies were all made for a date near full moon so that you can see the moon and stars moving alike. These show:
  1. From the equator stars move along paths at right angles to the horizon.

  2. From 40-degrees North, the stars move along paths inclined towards the south by 90-40=50 degrees.

  3. From the North Pole, stars move along paths parallel to the horizon.
Note:
In all of these movies, but especially in the North Pole movie, the projection of the hemispherical sky on to a flat movie screen results in an artifact whereby the paths are distorted. This distortion is most pronounced at the extreme edges of teh frames, and is most obvious in the North Pole movie, especially near the top of the screen.

Movie by Rick Pogge, composed using Starry Night Pro (v3.1.1)


Circumpolar Stars from Columbus, Ohio

1.4Mb QuickTime Movie

This movie shows the sky towards the North, with the pole star Polaris labeled from 8:03pm until 4:03am on the night of 1999 September 28/29 as seen from Columbus, Ohio. Columbus is located at 40 degrees North latitude, so Polaris appears at an altitude of 40 degress above the North horizon. All stars closer to Polaris than 40 degrees will neither rise nor set, hence they are "circumpolar" stars. Stars farther from the pole than 40 degrees are seen to rise and set as the movie progresses.

Movie by Rick Pogge, composed using Starry Night Pro (v3.0)


The Sun's Path along the Ecliptic through the Zodiac

8.4Mb QuickTime Movie

This movie shows the apparent annual motion of the Sun along the Ecliptic from 2000 September 29 (about a week after the Autumnal Equinox) at 2 day intervals until 2001 October 4, a little over 1 tropical year later. The Celestial Equator, and grid of the Celestial Sphere appear in red, while the Ecliptic appears as the Green line, with the Equinoxes and Solstices labeled. The 12 classical constellations of the Zodiac are also drawn and labeled so you can see how the Sun appears to move across the sky as seen against the background of the constellations. Normally, scattering in the atmosphere would prevent us from seeing the constellations, but this computer-generated view was made with no atmosphere turned on in Starry Night. Watch also as the various planets follow the Sun across the sky, especially Venus and Mercury, which always hover close to the Sun (the bright one is Venus, here somewhat exaggerated in brightness by Starry Night).

Movie by Rick Pogge, composed using Starry Night Pro (v3.0)


Moon Phases & Earth Phases over 1 Lunar Month

Moon Phases seen from Earth (3.2Mb QuickTime Movie)

Earth Phases seen from the Moon (3.0Mb QuickTime Movie)
These movies show time-lapsed views of what (a) an astronomer on earth would see looking up at the Moon, and (b) what an astronaut standing on the Moon's near-side at the location of the Apollo 17 landing (Taurus-Littrow Valley) would see looking up at the Earth at the same time over the course of a little over 1 Lunar Synodic Month. For both movies, the time step is 2 hours.

The astronomer on Earth sees:

  1. The Moon always keeps the same face towards the Earth.

  2. The Moon going through its phases, starting with Last Quarter and ending just a little after first quarter.

  3. The Moon moving against a changing background of stars as it orbits the Earth.

At the same time, the astronaut on the Moon sees:
  1. The Moon always keeps the same face towards the Earth (more or less) all of the time, since the position of the Earth in the Moon's sky is the same with respect to the Lunar horizon of our imaginary astronaut. The Earth neither rises nor sets, but stays fixed in the sky.

  2. The Moon is obviously rotating about its axis with respect to the stars, as you see the stars sweep past over the course of the Lunar month. If the moon were not rotating about its axis, you would see the same stars all of the time.
  3. The Earth goes through phases like the Moon, but Earth is also obviously rotating about its own axis each day.

  4. The Lunar sky is always black and filled with stars, even when the Sun is out, because it has not atmosphere. (Watch what happens about half way through the movie when the Earth is at its "New Earth" phase.

Both movies by Rick Pogge, composed using Starry Night Pro (v3.0)


2024 April 8 Total Solar Eclipse

5.5Mb QuickTime Movie
This movie shows the passage of the Moon's shadow over Central and North America during the total solar eclipse of 2024 April 8 (UTC). The dark central umbra is shown surrounded by the fainter penumbra. The eclipse shadow algorithm is not terribly sophisticated, so the penumbra appears uniform. In reality, the penumbra shades from the dark umbra to the edges (see this Mir image of the 1999 Aug 11 eclipse shadow).

Movie by Rick Pogge, composed using Starry Night Pro (v3.0)


Mars Retrograde Motion during 1994/95

688Kb QuickTime Movie
This movie shows the motions of Mars against the background stars from 1994 Sept 24 until 1995 July 4, during which time it passed through opposition and went into retrograde motion between 1995 January 2 and 1995 March 24. The time step is 1 sidereal day per frame. The object that rapidly flits through the frame repeatedly as the movie goes along is the Moon (Starry Night does not let me selectively turn off the other planets).

Movie by Rick Pogge, composed using Starry Night Pro (v3.0)


Geocentric Perspective of the Solar System in 150AD

2.2Mb QuickTime Movie
This movie shows 5 years of the motions of the Sun, Mars, Mercury, and Venus as viewed from above the ecliptic plane, taking a geocentric perspective in which we fix the position of the Earth and watch the evolution of the solar and planetary paths.

The movie starts by drawing the apparent paths of the Sun and Mars, following Mars through two episodes of retrograde motion as seen from the Earth (roughly 3 years). The paths of Mercury and Venus are then traced out for the rest of the animation (about 2 years time). These paths illustrate the complex motions that are seen when we take the perspective of a fixed Earth. It was this apparent complexity that the Ptolemaic System, with its complex machinery of epicycles and equants, was trying to describe.

Please note that this is not a simulation of the Ptolemaic System. Instead of trying to compute epicycles and equants, we instead compute the actual planetary motions around the Sun using modern Keplerian orbital elements, and then shift the frame of reference from the Sun to the Earth.

Movie by Rick Pogge, composed using Starry Night Pro (v3.0.2)


Ptolemaic & Copernican Solar System

2.8Mb QuickTime Movie
This movie shows the motions of the solar system from 1543 until late 1550 AD as seen from above the ecliptic plane. Two perspectives are shown:
  1. The perspective of a fixed earth, showing how the motions appear from a geocentric view point. Please note that this is not a realization of the Ptolemaic System proper: we are computing actual solar system motions seen from the reference frame of the earth.

  2. The perspective of a fixed sun, showing how the motions appear from a heliocentric view point. Again, this is not strictly the "Copernican" model as proposed in De Revolutionibus, as we are using computed actual motions, not a realization of the complex system of heliocentric epicycles proposed by Copernicus.
The first segment traces out the path of the Sun and Mars, showing Mars through one evolution of its retrograde motion as seen from the Earth. From this "geocentric" perspective, the true orbital paths of Venus and Mercury trace out complex looping motions. The second segment begins by stopping the motion, erasing the paths, and then shifting to the heliocentric perspective. We then watch the evolution of the orbits of the 4 inner planets (Mercury, Venus, Earth, and Mars) through one Martian siderial period (1.52 years), and the zoom out and view the orbits of the outer two of the 5 naked-eye planets, Jupiter and Saturn.

The orbital motions in both segments are the same, only the point of view (fixed-earth vs. fixed-sun) has changed.

The point of this movie is to show how complex the paths appear from the perspective of a moving Earth, and how much simpler they become when we shift our perspective to that of a fixed Sun.

Movie by Rick Pogge, using Starry Night Pro (v3.0.2)


The Solar System Movie

3.3Mb QuickTime Movie
This movie starts just above the north pole of the Sun and then pulls back upward out of the plane of the Solar System until the orbits of all the planets are in view, although for clarity, only the orbits of Mars through Pluto are visible; the inner 3 planets (Mercury, Venus, and Earth), are lost in the glare of the Sun.

Then the perspective rotates down towards the plane of the Solar System, allowing you to see the large tilt of Pluto's orbit. We then rotate about 120-degrees around the axis of the Solar System, again showing the orbits of the outer planets, and then finally rotate to a position above the south pole of the Sun.

Movie by Ari Solomon, using Starry Night deluxe (v2.1)


Other Versions

Romanian Translation

Updated: 2011 Dec 07
Copyright Richard W. Pogge, All Rights Reserved.