TopBox User Manual


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Fig. 1. The TopBox mounted on the tailpiece of the RRRT.

The TopBox weighs about 65 pounds fully assembled, including the SBIG STL-1001E CCD camera. When it is attached to the bottom of the telescope, about 12 pounds of counterweights must be added to the top of the telescope to maintain balance (Figures 2 and 3). The counterweights are mounted on two arc-shaped aluminum plate assemblies which clamp onto the telescope top ring. Individual lead blocks of various sizes may be attached to each plate on threaded rods at three different positions and secured by wing nuts. When installing and adjusting the counterweights, avoid dropping tools onto the telescope primary mirror by working from the rolling platform ladder with the telescope pointed far from the zenith.


Fig. 2. Counterweight set for balancing the RRRT with the TopBox.


Fig. 3. Configuration of counterweights mounted on the N quadrants of the RRRT top ring to balance the weight of the TopBox, which is offset to the S.

The telescope mounting flange of the TopBox is the circular top plate with six 1/2" diameter bolt holes equally spaced around its circumference. Before allowing this flange to hold the weight of the TopBox, verify that it is attached from its top surface to the four side panels by twelve countersunk flat head socket screws in a square pattern with three on each side. Also verify that the cover plate has been removed from the top surface of the mounting flange to allow light from the telescope to enter the box!

The mounting bolts are 1/2-20 x 3/4 socket cap screws. Be sure the threaded lengths of the mounting bolts are 3/4"; longer bolts may damage the delicate mirror mounts on the upper side of the tailpiece, and shorter bolts may not hold securely.

Working together using the rolling platform ladder and the edges of the pier for footing, two people can lift the TopBox up to the tailpiece of the telescope, locate it into place by fitting the mounting flange into the matching recess in the tailpiece, and install the mounting bolts. This task is most easily done with the telescope already counterweighted and pointed at the zenith, and with the filter wheel module and the camera removed from the TopBox to reduce the weight that must be handled. The N side panel of the TopBox is the one that carries the autoguider positioning slide; the S side panel is filled by the filter wheel module.

Last modified: Oct 3, 2012
David McDavid