For the dark current mode the exposure time is irrelevant, of course. In all of these modes, the camera control software also displays a sampled view of the most recently readout frame on the workstation monitor. In the focus mode, the shuttering and display is repeated indefinitely, and essentially the focus position can be acquired by moving the optical bench from the adjacent workstation, in real time. The guide camera produces an image of a solar disk on a television monitor in the observing room. The turret is controlled via a computer program with manual override with a hand paddle with four directional buttons and a step size button.
Target acquisition consists of acquring the sun, and zeroing in on the center of the solar disk.
At this point an image of the solar disk is generally visible on the guide camera display monitor, if not, the turret can be moved in elevation and azimuth using the hand paddle, to acquire it. The next step is to aim the telescope at the center of the solar disk. In effect the turret is moved in right asension and declination when these limb locations are registered by the software. At this point the telescope pointing is accurate to an astonishing degree. In order to minimize the effect of atmospheric turbulence on observations, the third mirror can be articulated rapidly provided a reference image is available.