... At Keck we use the graphical tool sky to plan observations and to control the telescope. ... The user controls the telescope by clicking on stars and an overlayed view of the instrument detectors. ... To point the telescope, the sky user selects a pointing origin with the mouse and then drags and rotates the instrument field until the desired orientation appears on the display. ... To point the telescope, the sky user specifies two points: a sky location and a detector location . ...