The telescope has a polar disc/fork-type equatorial
mounting, as illustrated in Figure 
,
which is supported by five axial and three radial hydrostatic oil-bearing
pads. The tube, a conventional open Serrurier truss
structure, supports the Prime-focus assembly or the Cassegrain
secondary mirror.
Figure: Schematic views of the INT from the east and north.
The telescope is operated under computer control and can
be pointed to between -6 and +6 hours in hour angle, and from
-30 
930
to +90 in declination, subject to a maximum
zenith distance of 70. Operation below the pole is possible in
principle but has never been implemented in practice.
Note that the lower windshield causes vignetting for zenith
distances > 55 and has to be raised for such observations. Figure
shows the area of sky accessible to the INT.