TopBox User Manual


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Fig. 1. Left: The TopBox autoguider assembly. Right: Interior detail of the pickoff mirror, focuser, and sliding stage.

Mechanical System:
The TopBox autoguider assembly is a traditional offset guider (sometimes called an off-axis guider) consisting of a diagonal pickoff mirror which directs light from the telescope to a small CCD camera externally mounted in a motorized focuser. These components are connected together as a single unit mounted on the moving stage of a motorized linear positioner, allowing guide stars to be selected from regions far enough to the E and W of the main CCD camera field of view to avoid vignetting by the pickoff mirror. To maintain alignment of the sliding optical assembly, the top end of the focuser mounting bracket is attached to a linear bearing that slides along a rail built into the frame of the TopBox. As shown in Fig. 2 below, the focuser protrudes through a set of sliding light baffles which it carries along as it moves back and forth in the E-W direction.

Fig. 2. Sliding baffle system for the autoguider focuser and camera.

Last modified: Sep 13, 2012
David McDavid