More on White Balance
If you plan to shoot only in the darkest time of the night, after the Astronomical twilight and before the astronomical dawn, you can probably use Auto mode since the brightness and color of the sky isn’t going to change significantly. You can cycle through the different modes of white balance, take reference images and decide which one you like best. I usually set it manually to 3700 Kelvin (between fluorescent and light bulbs), which gives the sky a bluish tone that feels natural to me.