Virtual Telescope 120K (+search!)

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Virtual Telescope! 120,000 real stars, 8 planets, 1 moon and 88 constellations that can be visualized and searched in Scratch in a virtual telescope.

- arrows to move the telescope
- [Z] + up/down to zoom in and out
- [S] + up/down to change the sensitivity
- [T] + up/down to change the date (planets will move accordingly!)
- [Space] to get a full render (this takes a few seconds)
- [A] to show/hide axis
- Click the magnifier to search for a star/planet/constellation
- Click on a constellation name to show it
- [C] to show/hide all constellations at once (beautiful sky!)
- Point to stars to get theirs characteristics (name, constellation, Flam/Bayer/HD/HIP/HR IDs, apparent magnitude, spectrum and luminosity)

Notes and Credits

-- April 18: Released the light version with "only" 10,000 stars. If the full version is too slow, use the light version instead:
-- April 18: Version 120K: the database now includes all of the 120,000 known stars! Downside, it takes even longer to load... :-/ Also fixed a display issue where some stars were missing.
-- April 15: Version 3: added a Search engine, fixed the colors, improved the display (more aesthetic), optimized things a little bit, fixed the position of Saturn, Uranus and Neptune
-- April 10: Version 2, with the solar system in real time!
-- March 28: FEATURED!! thank you!! :-) --

The project contains 100,000 stars from the HYG database (see

The position of the planets and Moon in the solar system is computed in "real time" based on this excellent article:

Because of a size limitation of Scratch, the star database is stored in a single variable that is converted into lists during startup. This can take a while! Once the first 10,000 stars are loaded, you can use the virtual telescope. The loading keeps going in the background. To get all features (full render, etc.) you will need to wait for the entire database to be loaded.

Of course, if performance is problem, you can always run this in Phosphorus:

Default sensitivity is 1 and is more or less what you would see with naked eyes. Increase the sensitivity to see more stars!

You can zoom up to x1000. This may be necessary to see multiple star systems.

Some objects are not represented: deep space objects, nebulae, asteroids, comets and artificial satellites.

Shared: 19 Mar 2015 Modified: 16 Oct 2015
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