pioneerspacesim/pioneer — pull request #1506 by Ae-2222 (2012-09-13 01:11:25+00:00)
Title: Enable position in orbit (time of 'year') and rotational phase (time of 'day') to be declared in custom systems definition.

This expands and exposes start values for orbit positions and position in spinning about it's axis.
* Rotational phase
* Lua example field for rotational phase: :rotational_phase_at_start(fixed.deg2rad(f(170,1)))
* Orbital Phase
* Lua example field for orbital phase: :orbital_phase_at_start(fixed.deg2rad(f(20,1)))

* Valid values are 0 to 2 PI (including zero but excluding 2 PI) or 0 to 360 using deg2rad.
* This allows **time of 'year'** and **time of 'day'** to be defined for any body orbiting another.
* Allows **relative positions** of bodies to be defined, enabling selection of interesting features for tidally locked moons, setting up of complex multiple body eclipses, correctly representing Sol (correct side of the moon etc., and tweaking of start conditions.

Earth start has been switched to Los Angeles (most other starport locations were on flat land due to coastal cities except one location which had terrain over buildings issues) and daytime selected.

There's plenty of scope for a new scenic start location now time of day/year can be tweaked.

Commit messages give details.

**Screenshots:**

Moon at default position (see position relative to venus):
![](http://i.imgur.com/5XIFS.png)

Moon with orbital phase increased:
![](http://i.imgur.com/ioARW.png)

Moscow default:
![](http://i.imgur.com/Rfx3q.png)

Moscow with 180 degree rotational phase shift (12 hours)
![](http://i.imgur.com/f7JE4.png)