Solar System Live, the interactive Orrery of the Web, has been a Fourmilab feature since 1995. It lets you view the entire solar system, or just the inner planets (through the orbit of Mars). Controls allow you to set time and date, viewpoint, observing location, orbital elements to track an asteroid or comet, and a variety of other parameters. Click on the title of any control to display a help page explaining it, or go directly to the help table of contents. You can compose a request with custom settings and save the results as a browser bookmark, allowing direct access to Solar System Live with all the controls preset to your own preferences. You can plot the orbit of an asteroid or comet by choosing it from the object catalogue and clicking the “⊚” (orbit) button.
Here is a Solar System Live plot of the planets as they will be on the 100th anniversary of Apollo 11’s landing on the Moon, 2069-07-20, plotting the orbit of Halley’s comet, which will be crossing the orbit of Uranus, outbound after its perihelion on 2061-07-28.
I have just posted version 2.4 of Solar System Live, which cleans up code, fixes a few potential vulnerabilities to malicious requests (which could not hurt the Web server or cause security problems but, at most, cause the user’s request to come back with a 500 error status), and updates the Web documentation accompanying the application. As of this release, complete source code for the Web application and Web documents are maintained on and available from the Solar System Live source code repository on GitHub, making it easier for those interested to download and install the code, track changes, report problems, and submit code for addition to the program.