Foucault Pendulum (WebGL)
Foucault’s pendulum is a device invented by French scientist Leon Foucault to prove the Earth’s rotation in 1851. The fact that the Earth rotates has been known for a long time, but it is the first … more
Astronomy Simulation
Kepler’s law
Kepler and Tycho Brahe There is an astronomer before talking about Kepler (Johannes Kepler 1571 ~ 1630). That’s Tycho Brahe. Tycho Brahe (1546-1601) is a famous Danish astronomer. With the development of astronomical equipment, he left … more
Doppler Effect
Doppler Effect We have heard an ambulance siren and felt that the ambulance is getting closer. When the ambulance approaches, the sirens sound higher, and when they move away, the sirens sound lower. That is, when … more
Apparent Magnitude, Absolute Magnitude, and Distance to Stars
Star brightness and apparent magnitude Hipparchus of ancient Greece distinguished the stars in the night sky according to their brightness. He classified the brightest star as ‘magnitude 1’ and the darkest star as ‘magnitude 6.’ The … more
Stellar Parallax – 3D VR
Parallax When an object is close to me, you can use a ruler to measure the distance. But, it isn’t easy to measure when the object is away from me. In this case, how can you … more
Why do we see only one side of the moon?
Why do we always see the same side of the moon? The moon’s rate of rotation and rate of revolution is the same.
Apparent Motion of Venus
All planets in the Solar System revolve around the Sun in a counterclockwise direction when one views them from the celestial sphere’s north pole. Mercury and Venus are inner planets in the Solar System. They are … more
Scale of Solar System
Press the button of the planet you want to go. Orbital radii of the planets has applied the average.
Daylight Map
* If you are asked to access your location, please allow it. * Your personal data is not stored on the server. * For iOS devices, please allow location access as follows. day and night The … more
3D Location of the Ursa Minor(Polaris)
Constellations and distance to stars If you look at the sky where there is no light on a clear night, there are so many stars that can not count. Thousands of years ago, the ancients linked … more
Latitude of Polaris
Latitude of Polaris Polaris is far from Earth. Thus, light from the North Star reaches parallel to the Earth. And since the earth is round, the North Star’s latitude varies depending on where it is observed. … more
Why does the moon seem to follow me?
Is the moon really following me? How can you explain that the moon looks follow I? The moon doesn’t follow me. For example, if I go forward with a car, the landscape seems to move backward. … more