sunlight through atmosphere

examples/scenes/lunar-eclipse.toml

@@ -4,14 +4,18 @@
 #
 #   resolved render --scene examples/scenes/lunar-eclipse.toml --lighting L1 --preview lunar.png
 #
-# At lighting L1 the Moon is inside Earth's shadow and dark. At L0 it is drawn without
-# Earth's shadow, as a full Moon. Earth's atmosphere bends red light into the shadow
-# and a real eclipsed Moon glows a dim red; the renderer does not model that yet.
+# At lighting L1 the Moon is inside Earth's shadow, lit only by the sunlight Earth's
+# atmosphere bends into it, dim and red, and brightest along its northern edge, farthest
+# from the shadow's axis. The exposure, 0.3 s, is 3000 times the example camera's, as a
+# photograph of totality would be. At L0 the Moon is drawn without Earth's shadow, as a
+# full Moon, thousands of times brighter, so L0 takes its own exposure of 1 ms.
 
 epoch = "2025-03-14T06:58:44 UTC"
 
 [camera]
 focal_length = 0.4
+exposure = 0.3
+exposure_l0 = 1e-3
 
 [observer]
 position = [-6956600.88, 697838.87, 344565.04]