ufo-sentinel-alien-spacecraft-canvas-print

 Sentinel implies purpose — a craft that's watching rather than moving, stationed rather than transiting. Most UFO imagery is about motion and abduction; a sentinel is the static version, which produces a different kind of image. The craft is present in the frame the way a guard is present: not doing anything visible, but doing something by being there. The question an image like this poses is what it's watching, which is the question you keep asking as you look at it. That quality of sustained uncertainty is harder to achieve than it looks.