Test Drive Apoapsys Solar

Apoapsys Solar

So, as you might imagine, will all the space-related WebGL tools that I’ve been making, I am learning a ton about orbits and astronomical software algorithms. Each of the tools have relied on the PlanetMaker API, which pretty much takes advantage of the SceneScript feature. They just converted the standard PlanetMaker view into whatever I needed. Yeah, until now.


I am in the middle of rolling everything I have learned so far into a new Solar System engine for WebGL, which I intend for it to be a general purpose space visualization and planetarium API. Though it should come as no surprise given the name, the primary focus so far has been on objects in our solar system. So far, I have it loading up 8 planets, 7 minor planets, 66 moons, 16 spacecraft, 9 comets, 10 asteroids and 3 satellites. I’m only a few edits away from allowing access to 5,500 satellites and some 10,000 near Earth objects (I wouldn’t recommend loading all that at once: your browser will actually catch fire).

Wrapped around the new engine is a sort of testbed user interface I’ve been calling Apoapsys Solar which contains controls to most of the internal API functions. View options can control what you’re looking at as well as where you’re looking from. Position the onscreen objects to true locations using the Start Date control. Mess around and you’ll figure it out.

Most of the available objects have presets that let you track them in the night sky, or set up a preconfigured view. Next to the names of each spacecraft, comet, and asteroid, click the little icon (external_link) to load up the tracker.  Or you can just tick the box to load it into the current view.

Needless to say, it’s pretty early in it’s development. If anything blows up (and something probably will), let me know. please?

For the technically inclined (or curious), this is a JavaScript API which relies on Three.js by Richardo Cabello for WebGL. I loosely followed the three.js design patterns to keep things familiar and interoperative, but also have a bit of legacy PlanetMaker design in there. As for the algorithms in there, I make use of these:

Meeus, Jean. Astronomical Algorithms
Richmond, Virg.: Willmann-Bell, 2009.
ISBN: 978-0943396613

  • Chapter 13: Transformation of Coordinates
  • Chapter 22: Nutation and the Obliquity of the Ecliptic
  • Chapter 25: Solar Coordinates
  • Chapter 47: Position of the Moon
  • Chapter 48: Illuminated Fraction of the Moon’s Disk
  • Chapter 49: Phases of the Moon

Duffet-Smith, Peter. Practical Astronomy with Your Calculator
Cambridge University Press; 3 edition (March 31, 1988)
ISBN: 978-0521356992

VSOP87 theory for the orbits of major planets.

Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009


Once I finally put in full production, trajectories will be updated from either the JPL Horizons system or Celestrak TLE sources on a (likely) hourly basis.



Check it out here: http://solar.apoapsys.com


Did I mention it also has some preset views:Moon of Jupiter PresetReal-time Moons of Jupiter

Transit of Venus 2012 PresetThe 2012 Transit of Venus

ISS PresetReal-time Location of the International Space Station

Maven PresetPosition of the MAVEN Spacecraft in the Night Sky

Lovejoy PresetPosition of the Comet Lovejoy 2013 RJ in the Night Sky

2014AA53 PresetPosition of Near-Earth Asteroid 2014 AA53 in the Night Sky

New Horizons PresetPosition of the New Horizons Spacecraft in the Night Sky

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