An auto-guider is a camera that locks onto a star and tells your mount via a cable to adjust its position if that star deviates from the dead-centre of the view it sees in a guidescope. The guide scope is attached and aligned to your main scope so this allows your mount to track your target very precisely. This allows you to take long exposures without incurring any star trails or blurring of the images.
NexImage is a one-shot color imager that replaces the 1.25" eyepiece on your telescope and connects to your PC via USB 2.0. The 1280 x 720 CMOS sensor provides high resolution images of the Moon, with enough sensitivity to reveal details on Jupiter and Saturn