5. Analytical aerial triangulation, compilation 
To the existing STK1 Stereocomparator, Wild in 196B added the 
B8 Aviograph for detail compilation from ultra uide and wide 
angle diapositives at the full 9" x 9" format. Whereas the B8 
has been fully described in (6) and several reports have 
appeared on the accuracy of the STK1, no constructional details 
of the latter appear in published journals. 
The Wild 5TK1 Precision Stereocomparator (Fig.5) is a tuo-plate 
instrument consisting of four horizontally-tiered, spindle- 
driven carriages arranged to provide a common x and y movement 
to both plates and a differential px, py movement to the right 
plate. This system has been found most convenient in practice 
since it not only eliminates time-wasting search for the same 
point in both pictures, it also saves the operator from the 
undue eye-strain inherent in this process. 
All spindles are now equipped with the correction device for 
the elimination of spindle (lead screw) errors. Movement of the 
plates is normally through two two-speed handwheels for x and y 
and one-speed handwheels for the small parallax movements 
px and py. However, couplings are provided as a standard feature 
for connecting the x and y spindles to externally-mounted servo 
motors. 
The STK1 has fixed optics with 6x, llx, 2Bx and 4Bx magnifications, 
Four sets of measuring marks, convenient to the magnifications, 
are built into the instrument. Dove prisms with the coupling de 
vice are provided for increased setting accuracy. For progressive 
measurement of a strip of stereograms, the left and right images 
are interchangeable. Comfortable viewing results from the ad 
justable eyebase and the squint-correction adjustments. 
The coordinate and parallax readings are displayed to l^u on 
bright dials. Automatic registration is however possible by con 
necting the EK6 Electric Coordinate Printer. The EK6 records 
an eight-digit point number (entered on the keyboard of the 
control console) and the four values x, y, px and py to single 
microns; it replaces the earlier even-micron recording EK4. The 
EK6 can also be connected to a Wild A7, A8 or A9 Autograph when