Autoguiding basics

Motorized astronomical mounts track the celestial rotation, allowing the telescope to remain pointed at a set object for hours. For this to work, the mount must be precisely aligned. For instance, the polar axis (or hour axis) of an equatorial mount must point as accurately as possible toward the celestial pole.

However, in astrophotography, simply aligning the mount as accurately as possible is not enough. Depending on the exposure time, mechanical inaccuracies in the mount become noticeable. The longer the desired exposure, the more pronounced these effects are. The mount's tracking must be constantly monitored and corrected. For this, guiding aids such as a guide scopes with guide scope rings or an off-axis guider are required.

If the mount's correction is performed automatically, it is called autoguiding. This requires a camera and a control system that constantly sends impulses to the mount. Suitable cameras can be found here in the Astro Cameras category.