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Computing planetary positions – a tutorial with worked examples (2003)
- yoha 12y agoSome of the links from http://www.stjarnhimlen.se/comp/ppcomp.html#22 http://www.stjarnhimlen.se/comp/ppcomp.html#22 are dead. If you want human-readable physical and orbital data for: * planets, go to http://ssd.jpl.nasa.gov/?planet_phys_par http://ssd.jpl.nasa.gov/?planet_phys_par and http://ssd.jpl.nasa.gov/?planet_pos http://ssd.jpl.nasa.gov/?planet_pos (it points you to a table http://ssd.jpl.nasa.gov/txt/p_elem_t1.txt http://ssd.jpl.nasa.gov/txt/p_elem_t1.txt where elements need to be corrected for a given date, see http://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf http://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf) * moons, go to http://ssd.jpl.nasa.gov/?sat_phys_par http://ssd.jpl.nasa.gov/?sat_phys_par and http://ssd.jpl.nasa.gov/?sat_elem http://ssd.jpl.nasa.gov/?sat_elem * dwarf planets, asteroids, etc, go to http://ssd.jpl.nasa.gov/sbdb.cgi http://ssd.jpl.nasa.gov/sbdb.cgi Also, some more data here http://ssd.jpl.nasa.gov/?constants http://ssd.jpl.nasa.gov/?constants. If you want more precise orbital elements at a given epoch (they vary through the year), use http://ssd.jpl.nasa.gov/?horizons http://ssd.jpl.nasa.gov/?horizons (using the Telnet interface, first choose "Ephemerides" (e) and then "Elements" (e).
- davidw 12y agoApropos - does anyone have suggestions for good Android apps for things like this? I'm looking for something pretty for my kids, that lets you look at some different things, like how the moon goes around the earth, night and day on the earth, seasons, and maybe some of the other planets too.
- bengali3 12y agonot sure about mobile, but I would think Kerbal Space Program has most of the physics done, as well as an active mod community. I've always thought an accurate solar system mod would be pretty cool
- Lambdanaut 12y agoIt exists. Check this out: http://forum.kerbalspaceprogram.com/threads/55145-0-90-Real-Solar-System-v8-5-Dec-23 http://forum.kerbalspaceprogram.com/threads/55145-0-90-Real-... It's also a lot more difficult than the stock solar system.
- 32faction 12y agoKerbal Space Program has a good physics model for fun but not for study: it's very basic. Their drag and aerodynamic model for example is not accurate (if I remember correctly they assume drag to be constant) Jet engine modeling and life support are not accurate either
- sizzzzlerz 12y agoIt's a web site but it has a number of simulations of various astronomy topics and is very well done. It's labeled as being introductory but, depending upon the ages of your children, it might still be too advanced. http://astro.unl.edu/naap/ http://astro.unl.edu/naap/
- sizzzzlerz 12y agoIf you're interested in this type of computation and have some basic knowledge of Python, there is a package called pyephem that you can install that allows you to perform all sorts of calculations on the planets and other astronomical bodies. It uses the same ephemerides data set that is used by professional astronomers so it is quite accurate.
- vamin 12y agoPyKEP (https://esa.github.io/pykep/ https://esa.github.io/pykep/) is also quite good.
- amelius 12y agoDoes it show how to compute the error margins?
- McUsr 12y agoIt is a great fun to compute Planetary positions. You should really read a book named "Astronomical Algorithms" by Jean Meeus. That is the ultimate source for those computations, for hobby use. (There is a really nice chapter in there, about accuracy, and interpolation of values). You'll find various implementations of the algorithms on the net.