Calculating the Sphere Mount Locations

This document describes the recommended process and method for suspending the sphere.

The sphere is suspended from three eyebolts mounted directly in the ceiling by the site. Three suspension wires allow the sphere to find its own stable plane. The angle of the suspension wires should be in the range of 15 to 20 degrees (we recommend 20 degrees). If the angle of the suspension lines from the sphere to the ceiling is too acute, the sphere can be susceptible to vertical instability (bouncing). Too steep an angle can make the sphere susceptible to pendulum instability (swaying).

The basic approach is to layout the footprint for the SOS exhibit. The projectors are at the corners of a square, with the sphere positioned in the exact center of that square (see the floorplan diagram for reference). Conceptually, it is easiest to think of the sphere hanging from three points, which are at the corners of an equilateral triangle of some size. The size of the triangle is determined by the angles of the cables coming out of the sphere and the height of the ceiling. Low ceilings require smaller triangles, while high ceilings require larger triangles. The triangle points need to all be on the same plane and that plane needs to be parallel to the floor in order to have sphere hang where you expect it too.

One of the more difficult dimensions to come up with is the length of the sides of the triangle. To simplify the process of determining this length, use either the Sphere Mount Triangle Calculator below or download the provided Microsoft Excel Spreadsheet.

Simply input the ceiling height and it will output the parameters needed to create the triangle.

Ceiling Height (feet) Up to one decimal place of precision is allowed

Calculate

Distance from eyebolt to center of sphere

56.1 inches

Distance from center of sphere to triangle edge

28.0 inches

Distance between eyebolts

97.1 inches

Distance from eyebolt to midpoint of triangle edge

48.5 inches

Distance from center of sphere to ceiling

154.0 inches

Distance from top of sphere to ceiling

120.0 inches