Velocity effects (lighttime, aberration)

readme.md

@@ -83,6 +83,9 @@ let scene = Scene {
     // Which way the Moon's surface map faces; an ephemeris gives it exactly.
     moon_attitude: Scene::moon_facing_earth(moon),
     targets: vec![Target { model: panel, pose: Pose::new(target, UnitQuaternion::identity()) }],
+    // From camera C1, what makes positions apparent; an ephemeris gives Earth's and
+    // the Moon's, and the observer's is the simulation's.
+    velocities: Default::default(),
 };
 let observer = Pose::looking_at(target + Vector3::new(20.0, 0.0, 0.0), target, Vector3::z()).unwrap();
 
@@ -190,10 +193,11 @@ L1 draws Earth's surface from Blue Marble and the Moon's from the LRO Camera's
 map, shadows on the target, light from Earth and the Moon on it, eclipses on
 Earth and the Moon, and the Sun's limb darkening. Camera C1 is under way: so
 far, pixels that collect light over their area, lens distortion
-(Brown-Conrady), and lens blur (a Gaussian PSF) applied to the scene
-rendered 2 x 2 finer than the pixels. Planned, in order:
+(Brown-Conrady), lens blur (a Gaussian PSF) applied to the scene rendered
+2 x 2 finer than the pixels, and the Sun, Moon and Earth at their apparent
+positions (light time and aberration). Planned, in order:
 
-- Camera: apparent positions, stars,
+- Camera: stars,
   detector noise, pixel-to-pixel variation, saturation and blooming.
 - Lighting: BRDF and spectral materials, atmospheric scattering, clouds, lunar
   terrain.