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
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:
- From the equator stars move along paths at right angles to the
horizon.
- From 40-degrees North, the stars move along paths inclined towards
the south by 90-40=50 degrees.
- 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)
- 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)
- 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 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:
- The Moon always keeps the same face towards the Earth.
- The Moon going through its phases, starting with Last Quarter
and ending just a little after first quarter.
- The Moon moving against a changing background of stars as it orbits the
Earth.
At the same time, the astronaut on the Moon sees:
- 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.
- 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.
- The Earth goes through phases like the Moon, but Earth is also obviously
rotating about its own axis each day.
- 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)
- 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)
- 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)
- 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)
- 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:
- 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.
- 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)
- 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)
Updated: 2011 Dec 7
Copyright © Richard W. Pogge,
All Rights Reserved.
