var viewer = new Cesium.Viewer('cesiumContainer', {
orderIndependentTranslucency: false,
contextOptions: { webgl: { alpha: true, } },
});
viewer.scene.skyBox.show = false;
viewer.scene.backgroundColor = new Cesium.Color(0.0, 0.0, 0.0, 0.0);
//viewer.scene.skyAtmosphere.show = false;
//viewer.scene.skyAtmosphere.brightnessShift = -0.0;