sun: add configurable warm corona glow

config.js

@@ -650,9 +650,18 @@ window.CONFIG = {
     // scene lighting are NOT scaled with it.
     sun: {
         angularRadius: 0.0279,    // 6x the physical 0.00465 rad
-        brightness: 1.8           // sun disc/halo gain
+        brightness: 2.1,          // sun disc/glow gain
+        glow: {
+            enabled: true,
+            core: 1.15,           // bright inner corona
+            inner: 0.95,          // warm near halo
+            outer: 0.38,          // soft far halo
+            outerRadius: 11.0,    // outer halo radius in sun-disc radii
+            color: [1.00, 0.78, 0.36]
+        }
         // angularRadius: 0.0558, brightness: 1.0
         // angularRadius: 0.0140, brightness: 2.4
+        // glow: { core: 1.6, inner: 1.4, outer: 0.55, outerRadius: 14.0 }
     },
 
     // ------------------------------------------------------------------