The Astrophotography Manual, 2nd Edition

Autoguiding and Tracking

A perpetually thorny subject, laid bare to develop into robust strategies.

 

 

 

One way or another, successful imaging requires a telescope to track the star’s apparent motion, to an incredible accuracy, over the duration of each exposure. For focal lengths of about 1,000 mm, critical work may require ±1/7,000° RMS (±0.5 arc seconds). In context, this is equivalent to the thickness of plastic food wrap film at a distance of 5 m. For many, this is achieved by autoguiding in combination with good polar alignment. Others use a precise tracking model and dispense with guiding altogether. For clarity, they now have their separate chapters. Autoguiding and modeling have many interactions, however, since they are applied ...