The Horsehead nebula can be seen in this portion of the "first-light" image from ZTF. The head of the horse (middle) faces up toward another well-known nebula known as the Flame. Violet to green wavelengths detected by ZTF are represented as cyan, while yellow to deep red wavelengths are shown as red. Computers searching these images for transient, or variable, events are trained to automatically recognize and ignore non-astronomical sources, such as the vertical "blooming" lines seen here.