The MKIA Radio Telescope By the late 1960's it was becoming
apparent that the steelwork supporting the bowl in the vicinity
of the tower tops was being over stressed. A plan was thus drawn
up to take away around a third of the load from the towers and
pass it through two large semi-circular wheel girders to a new
central rail track. However it was vital that the rotation axis
(the line through the elevation bearings) still remained very
close to the centre of gravity of the combined bowl and wheel
girder structure otherwise it would not be possible to rotate
the bowl in elevation. To counter balance the new wheel girders
it was thus necessary to place additional weight on the far side
of the axis. This was done in by far the most productive way -
by building a new surface within the old! The original surface
was a a deep parabaloid with its focus in the plane of the
aperture. This gave it excellent protection from interference,
but also meant that the effective collecting area was less than
optimum. The new s