1) a part of parallelepiped rectangular shape, furnished with
supporting feet and foot screws, which supports the coordinatometer;
2) the U-shaped bench which supports the projecting and the
plotting units.
b) This group affords the interchangeablility of a pair of projecting
cameras, each size cm. 18 x 18 (7 */,," x 1 3/22) for film and plate. The first
pair of normal type is furnished with OMI Aldebaran lens focal length
em. 21 (8/,,"); the second pair, of wide-angle type, with lens Omigon
having a focal length of cm. 125 (4*/.."). The first pair can be used
for plotting from photographs obtained with the film camera FOMA (3),
OMI make. It can be all the same employed for plotting from pairs taken
with any other camera, provided the original photograph is transformed
into another corresponding, as to its geometrical characteristies, to those
of the plotting camera; this can be obtained with the OMI orthoscopic nor-
mal Photoprinter, or optionally with the « Nistri» telescopic Photoprin-
ter, which allows of respecting Porro's principle even when plotting.
Either instrument represents the normal outfit of this plotting appa-
ratus (4).
Both cameras are individually supported by a special cardanic device,
which allows for them to assume the three augular independent positions
of outer orientation (longitudinal ®, transversal 9 and swing K) with an
approximation of 1/100 of centesimal degree.
These cardanic devices are supported on their turn by two camera-
bearing arms, rigidly connected by means of a bridge of cylindrical shape,
rotatable according to an axis disposed in the X direction, representing
the flight direction.
The width of rotation of this bridge around its axis is represented
by the angle ©, which is attributed contemporarily to both cameras at
at the moment when the model is horizontalized: see fig. 1,.2, 3, 4.
This bridge in its turn is supported by a sleeve, by means of which
it can rotate around a vertical axis, having therefore the Y direction.
Such rotation, which acts at the same time on the two cameras in the
longitudinal sense of the flight, is made in order to obtain the horizonta-
lization given by the angle 9. These two angles can be included within
the interval + 10% The angle of absolute orientation (K) around an axis
which is parallel to the Z axis of the height, can be obtained on the car-
(3; See: G. Boaga — Moderna apparecchiatura « Nistri» per la costruzione delle
carte aerofotogrammatiche — (Modern « Nistri» equipment for drawing aeropho-
togrammetric maps) — Communication to the VII National Congress of Aerotech-
nies — Pisa, Sept. 23-25, 1945.
(4) See. G. Parenti — Aspetti pratici del problema della riduzione nell’impiego
di restitutori multipli — (Practical sides of the problem of reduction in the employ-
ment of Multiplex plotters) — edited by « Rivista del Catasto e dei Servizi Tecni-
ci Ereriali» year 1950.
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