Instruction:

1. In your scene: File -> Append (shift+F1) -> Select “Sky_Environment_shader_v.2.blend”

2. World-> “Sky Environment shader v.2” to load already setup world shader;

3. Go to Shader Editor -> Switch “Object mode” to “World” & select “Sky Environment shader v.2” from World list

4. Tweak Mapping nodes in Movement controll area to controll movement & animate clouds, stars & horizont line;

5. Use Sky’s Presets & Transition node to change color mude or Use Sky Surface + Color correction nodes to add custom values.

6. If you want to create your own preset, enter to Sky’s Presets & Transition node (select node & press Tab) & in Custom color area tweak gradient node by piсking colors from custom photo of sky.

7. To swich between Day/Night use appropriate swicher in Sky’s Presets & Transition node

8. In Compositing use Glow node for add Glow effect.

Tip for Sky Environment shader v.1
If you have already rendered environment without clousd (alpha channel) use:

1. Background Day socket for day scene

2. Background Night socket for night scene (you can do night scene using curver & day scene, like in movies

3. Background alpha - for masking background & Sky Environment Shader)

Enjoy!

YouTube:

demo of Sky Environment shader v.2:

demo of Sky Environment shader v.1:

demo: https://youtu.be/6V9mGxboD6Y
example.1 - https://youtu.be/6V9mGxboD6Y
example.2- https://youtu.be/6nEUaDTWFPY
example.3.1 - https://youtu.be/WJdMmVazawA
example.3.2 - https://youtu.be/E9wMwwLDhnA
VR view - https://youtu.be/8XPblsC7qic 

Enjoy!