anchor.diff:                      let polColLum = Vec.dot (polCol.ToV3d()) lumVector
                       pol * polCol.SRGBToXYZinC3f().ToC3d() / polColLum
       
  -                let sunScale = nightTimeFadeout theta
  +                let sunFadeout = nightTimeFadeout theta
  +                let moonFadeout = nightTimeFadeout thetaMoon
                                          
                   let cubeFaces = Array.init 6 (fun i -> 
                       PixImage.CreateCubeMapSide<float32, C4f>(i, res, 4, 
                           fun v ->
                               let mutable xyz = C3f.Black
  -                            xyz <- xyz + skySun.GetRadiance(v).ToC3d() * sunScale
  -                            xyz <- xyz + skyMoon.GetRadiance(v).ToC3d() * 2.5e3 / 1.6e9 * moonRefl // TODO: actual amount of reflected light
  +                            xyz <- xyz + skySun.GetRadiance(v).ToC3d() * sunFadeout
  +                            xyz <- xyz + skyMoon.GetRadiance(v).ToC3d() * 2.5e3 / 1.6e9 * moonRefl * moonFadeout // TODO: actual amount of reflected light
                               xyz <- xyz + (lightPolFun v) * pol
                               let rgb = xyz.XYZinC3fToLinearSRGB().Clamped(0.0f, Single.MaxValue)
                               if rgb.ToV3f().AnyNaN then 
  
positive.code:                     let s = starDict.[hip]
                      if s.Hpmag < float32 t then 
                          // distance = size
                          // TODO/ISSUE: angle offset woul get rotated by star trafo
                          let t = Trafo3d.Scale(0.15) * Trafo3d.Translation(10.0 * Conversion.CartesianFromSpherical(s.RArad, s.DErad))
                          Some (AVal.constant(t), AVal.constant(str))
                      else 
  
negative.code:     
                  let lum = geoInfo.JulianDayUTC |> AVal.map (fun jd -> 
                      let rc = Astronomy.RectangularHeliocentricEclipticCoordinates(p, jd)
                      let distKm = rc.Length * Astronomy.AU / 1000.0 // convert to km
                      let sunRadiusKm = 695700.0 // km
                      let sunLuminance = 1.6e9
                      let a = atan (sunRadiusKm / distKm)
  