Abstract: Electro-optical tube alignment apparatus having a monitor for monitoring shading of the tube image, an adjustment device for adjusting tube target bias voltage so that shading is introduced into the image and is monitored by the monitor, and a control for varying tube alignment until a minimum average shading is monitored. Also beam current setting apparatus in which switch devices are provided to switch off the beam current during field scans so that the target charge during setting exceeds that produced by an operational peak light level. Methods associated with the apparatus are also provided.