At night all color is gone. When you photograph nature at night, you and your camera see shades of gray — that is, unless you use long exposures of several minutes. When you do this, you start to see color and the black sky becomes blue.
To photograph at night, shoot in Bulb (B) mode. This leaves the shutter open as long as the shutter button is pressed. You can use a cable release or a remote trigger to accomplish this. However, this can get tedious with long exposures that are several minutes in duration.
If you enjoy photographing nature at night, consider investing in an intervalometer, a device that enables you to program the amount of time you want the shutter to remain open.
When you photograph a scene that will be rendered as a silhouette, you can get creative and use a flashlight to illuminate certain parts of the scene. This requires some experimentation on your part. The exposure will be a bit of a crapshoot, depending on the brightness of your flashlight and the amount of ambient light.
Long exposures drain batteries quickly. You can solve this problem if you have an AC adapter for your camera and available AC power.
Photographing a scene with the moon in the sky is tricky. The moon is much brighter than anything else. If you expose the scene for the landscape, the moon will be a bright blob in the sky. If you’re photographing a mountain range, you can expose the image so that the moon is properly exposed. This will render the scenery as a silhouette.
Done right, this can be the formula for a compelling photograph. Compose the image so that the moon is a focal point.
The alternative to photographing a landscape with the moon as a silhouette is to take multiple exposures of the image and blend them with HDR software.