AstroApps
One focus of the following apps is to present the basics of astronomy in a graphically appealing way. After a click on Run Application a new window opens with the respective app. A short help can be found in the upper right corner under ''Help''. The visual representation is based on the graphics programming interface WebGL and especially the threejs-library. The d3js library is also used in some cases. Further information about the sources used can be found in "About".
If you want to link to these AstroApps, please use this link: https://www.haus-der-astronomie.de/vis/astroapps
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Star Trails With the app "Star Trails" you can visualize the apparent course of the stars on the celestial sphere. At various locations on Earth, you can display the visible part of the celestial sphere and follow the course of various stars on it. Real data and a free movement of the camera in 3D allow a variety of uses: rotation of the Earth as the reason for the apparent movement, influence of the observation location, rising and setting, (upper) culmination, circumpolar stars. |
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Seasons The obliquity of the Earth's axis by about 23.5° is the reason why there are seasons on Earth. |
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Moon Phases The app "Moon Phases" shows the movement of the Moon around the Earth illuminated by the Sun from a freely selectable perspective. This allows you to visualize not only the formation of the moon phases and the bound rotation of the moon, but also the (rare) occurrence of eclipses. By skilful choice of the observation time, the simulation speed and the object scales, the orbital period and the rotation period of the moon as well as the shape, size and orientation of the moon's orbit can be determined. |
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Solar Eclipse The orbital plane of the Moon around the Earth is slightly tilted compared to the orbital plane of the Earth around the Sun. Therefore, the Moon's shadow does not hit the Earth every time there is a full moon. Only at rare constellations, precisely when the connecting line between the Sun and the Moon (shadow ray) hits the Earth, can a solar eclipse be experienced from certain places on Earth. |
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Sundial The horizontal sundial can display the time at the respective location via the shadow of a rod. Here, the sundial can display either the true solar time for a certain longitude and latitude or the actual UTC time. |
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Stellar Parallax If one observes the position of a nearby star in the course of a year, it appears to change against the background of very distant stars (celestial sphere). Depending on the distance of the star to the observer, this parallax takes a different angle. |
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Orbital Elements The orbit of a planet around its star can be approximated by an ellipse. This in turn is determined by its large semi-axis and its eccentricity. The position of the ellipse... |
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Bright Stars in HRD The app "Bright Stars in the HRD" enables the transition from the observation of stars as simple light sources of a known starry sky to objects with physical properties. The step-by-step entry of pairs of values (luminosity and surface temperature) into a diagram results in an arrangement of data points that leads to the Hertzsprung-Russell diagram. The HRD is considered as a state diagram of the stars. |
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Constellation Explorer The constellations in the night sky give the impression that the stars are spatially close to each other. In fact, the stars of a constellation have very different distances to the Earth, which can only be recognized in a three-dimensional representation. |
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Constellation Explorer V2 The constellations in the night sky give the impression that the stars are spatially close to each other. In fact, the stars of a constellation have very different distances to the Earth, which can only be recognized in a three-dimensional representation. |
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Radial-Velocity-Method A planet and its star orbit their common center of mass. Depending on the direction of observation, this results in a radial motion of the star, which can be detected in the Doppler shift of the stellar spectrum... |
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Transit-Method If an exoplanet passes in front of its star from our point of view, the light of the star is weakened. But since the exoplanet also reflects the light of its star partially, the total radiation flux can also become larger than that from the star alone... |
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Expansion On Transparencies Are we at the center of the universe? |
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Galactic Center Stellar Orbits In the center of our Milky Way there is a supermassive black hole. It is orbited by numerous stars, and the star "S2" is one of the most interesting of them, because more than one orbit could be observed and it confirms the general relativity theory in the best way. |
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Hubble-Lemaitre-Relation for Galaxies The Hubble-Lemaître relation links the distance to an object with its redshift. This app makes it possible to explore the Hubble-Lemaître relation for yourself - namely, select galaxies in the sky for which the required data are available; the data points are then automatically entered into a corresponding diagram. |
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Gravitational Lenses Masses curve the space-time and light follows this curved space-time and is deflected thereby. If there is a large mass between us and a distant object, the object appears distorted due to the deflection of light. |
