This is a Night Portrait icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 12,500 icons, all in the same style and quality.
It is a simple representation of a night landscape. the top right has a crescent shaped moon and next to that is a circle. Beneath the circle is something that resembles a hill. it has a straight line for a base and a shape that looks slightly like the letter M attached to it