Asteroids - Dynamic Site
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This web site provides data on numbered and multiopposition asteroids, including orbital elements, their uncertainty, proper elements, ephemerides with uncertainty, and more.


The orbits and other information, as posted on the web page of each individual object, is periodically recomputed if new observations are available, with the OrbFit free software.

The following catalogs are updated every month, or anyway whenever the MPC releases a full update of the dataset: osculating orbital elements, analytical proper elements for Main Belt asteroids, residuals and quality control after the orbital fit. Other catalogs, such as synthetic proper elements, are updated periodically. The last monthly update has been based upon the observations performed until May 15, 2024.

What's new?

How does it work?

These important buttons and links are at the top and bottom of every page:

To browse the list of objects in the AstDyS database.
To browse the list of observing stations.
To search for a specific object or for objects with particular characteristics.
Orbital elements
Catalogs of Orbital elements
Proper elements
Catalogs of proper elements
Related sites
Links to related WWW sites.
Info & Credits
Information page: about AstDys, frequently asked questions, MJD conversion tables and other infos.
Help window.
This is the Tools icon (on the right in the top banner). Clicking repeatedly on it shows the following tools: Go to asteroid, Current date-time, MJD-calendar conversor and, finally, color and font-size selectors. When all the tools are displayed the icon changes to  ▼ . Clicking on  ▼  hides the tools and sets the icon again to  ▲ .
Expands the main content area, hiding the banners and menus, to increase the available on-screen surface for data browsing. The same icon lets you restore the initial layout.
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Send feedback to the AstDyS team.