Sunday, 2 February 2014

Soltan Ephemeris

I've been very busy working on maps for the +World of Calidar since I last posted.  +Bruce Heard has shared some of the results on his blog, and today I'd like to share another variation of the Soltan Ephemeris diagram.

Soltan Ephemeris triple-scaled diagram, showing orbital distances, relative planet sizes, and moon orbits of Calidar and its neighbours.

The same diagram is on Bruce's blog post, but in vertical form.  Both were a lot of fun to make.  I started off trying to use scaled measurements from a chart I've been keeping with all the precise measurements of the planets, before realising that I could simply resize the existing diagram to get all the orbits at their proper scale.

Soltan Ephemeris Overview and Orbital Map, showing Draconia, Calidar and its moons, Lao-Kwei and its moon, the Fringe, and Ghüle.  Solar System Map.
Soltan Ephemeris Overview and Orbital Map
as featured on Bruce's blog.
There is an intrinsic problem with trying to make a scale diagram of any solar system: the distances between a star, its planets, and even their moons are so great that they reduce even the largest star to a small point in space.  What this means is that a properly to scale diagram is pretty useless.

To get around this issue, I have split the image into three different scales.  Each scale is consistent only within its own domain.
  1. Orbital distances: all planetary orbits are to scale with each other, measured from Soltan's corona.  The orbits shown are at the 3 o'clock position on the orbit diagram.
  2. Planet sizes: all planets, including moons, are to scale with each other, and indeed with Soltan. But Soltan is so massive that only a tiny portion is visible in this diagram.
  3. Lunar orbital distances: all lunar orbits are to scale with each other, measured from the centre of their parent planet.  They are not in scale with planetary orbital distances; putting them in scale would make them overlap with the orbs of the planets.
There is one further issue: Ghüle is so distant when it's in the 3 o'clock position that it would require the diagram's width to be more than doubled in order just to fit it in.  Moreover, its orbit takes it much closer to the sun at other points, so there is no single logical distance to display it at.

Soltan Ephemeris triple-scaled diagram, showing orbital distances, relative planet sizes, and moon orbits of Calidar and its neighbours.  Ghüle is in its proper position.
Ghüle in its correct 3 o'clock position.
As a result, we have chosen to arbitrarily show it at a more reasonable distance outside the Fringe.  It actually does pass through this position at two points of its journey around Soltan, once before passing inside the Fringe, and again after passing outside again.  I think it's a good compromise.

These diagrams are actually mock-ups, waiting to be populated with marble-like globes, such as the Calidar rendered globe we used in the Kickstarter campaign.  You'll have to wait a while longer to see those, but I hope I can make it worth the wait.  The final version will likely be featured in the final book, too.

One final note: as you may have already noticed, I have added a permanent page devoted to the Soltan Ephemeris Calculator, accessible through the buttons under the site heading above.  This allows easy calculation of the exact positions of the worlds of the Soltan Ephemeris by inputting a date on the Calidaran calendar.
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