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The ability to separate two objects on the night sky is determined by the resolving power of the eye, or instruments being used to observe the heavens.
A telescope (special lens/mirrors system) increases the apparent visual size of the observed body.
|Atmospheric Effects - Particulates
Particulates in the atmosphere cause light to be scattered. This has two effects - firstly to diminish the brightness of the stars and secondly to increase local scattered light.
|Atmospheric Effect - Heat
The warmer the atmosphere the more turbulent it becomes. This means that the light path through the atmosphere is changing so objects appear to brighten and fade (twinkle).
|Atmospheric Effects - Light Pollution
Light given off from local sources (such as street lights) brightens the sky and makes it harder to see fainter objects.
|Flight to the Moon
A simple animation showing how a spacecraft transfers from orbit around the Earth to an orbit around the Moon
The ESA Gaia mission will be placed in a Lissajous orbit at the second Lagrange point.
|3D Model of Milky Way
An interactive 3D model of our galaxy that allows you to rotate, zoom in and out and select the objects to be viewed.
|Measuring the Milky Way
Explore the difference between Hipparcos data gathered after 1989 and that projected for Gaia.
|Effect of Gravity on Light
The illustration shows how light deflection depends on the mass and the size of a celestial body.
|Radial Velocity via Doppler Effect
The illustration shows Doppler's effect which is the change of frequency of a signal when the source of the signal moves either away from us or toward us.
Early astronomers used the sextant to measure the positions of the stars.
This illustration shows how parallax affects our perception of the apparent position of a star near to us.
The illustration demonstrates the formation mechanism for an emission spectrum and an absorption spectrum.
Search for Planets
|Solar System Formation
A simulation showing how the soalr system formed.
In this simulation, you see a hypothetical star system with one planet orbiting the star.
Light rays traveling from the background star towards us pass very close to the second 'lensing' star, and the gravity of the latter bends the light path just as a lens system would.
|Formation of Planets
A short QuickTime movie that describes the formation of the planets.
A simple QuickTime movie that shows the positions and motions of asteroids located in the asteroid belt.
Last Update: 4 May 2022