A method of correcting imaging errors for a telescope by referencing a field of view of the telescope is used to replace the need of a guide star and the related use of centroid techniques with the guide star. In order to accomplish this, this method uses the full frame of a supplemental camera for both auto-guiding and auto-focusing. All of the guider frame is used to retrieve focus and directionality information for auto-focus, but without the need of a specific guide star. This method uses any astronomical feature and structure, such as galaxies, nebulae, clusters, stars, etc., for retrieving image focus information (from the latest guider frame) to compute auto-focus and related focuser corrections, including the direction of the correction (in or out).