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The Rockwell Turbo Commander 690A will be used, with and without a window,
and flight altitudes will be maximized in accordance with the target control
area.
Hans-Karsten Meier is scientific director of the Carl Zeiss Survey Depart-
ment. He has studied geodesy at Hannover Technical University and joined
Carl Zeiss in 1955. In the same year he obtained a doctor degree (Dr.-Ing.)
at Munich University with a thesis on plumb-line-deflections. Since then
he published about 75 papers dealing with geodetic and photogrammetric
problems. Together with Professor Ackermann he is organizer of the Photo-
grammetric week.
Meier's WG-3 study is concerned with the environments of pressure and temp-
erature. He has initiated many technical studies on photogrammetric sensors,
calibration equipment, and techniques, being concerned with image quality and
geometry both in the laboratory and under conditions of use. The later lead
to his investigation of the effects of aerial survey environments on the
geometry of Zeiss cartographic lenses.
"The Effects of Environmental Conditions on Distortion, Calibrated Focal
Length and Focus of Aerial Survey Cameras" is the title of Meier's invited
paper to Working Group - 3 Panel. The theoretical study examines the changes
in four Zeiss mapping lenses for the above characteristics, under three en-
vironmental conditions for cameras at altitudes of 6 and 14 kilometers.
In the first "protected" case the camera is assumed to be installed in a
pressurized cabin viewing the terrain through a window or cover glass of
specified thickness. In the second and third cases the camera is exposed
to the atmosphere (no window); but in one case the camera is at atmospheric
temperature and pressure while in the other case it is subjected to cabin
heating, the opening around the camera being sealed. Measurements have
shown this temperature to average out at +7°C, under which conditions lens
computations show changes in distortion. ;
The S-Pleogon À 4/85 shows a maximum positive change of seven microns at a
radial distance of 75mm (as estimated from the distortion curve) when installed
in a pressurized cabin with a window 45mm thick, at an altitude of 14 km.
The same camera exposed to the atmosphere at 14 km where the lens and external
temperatures are the same, shows a negative change of six microns at 100mm
radius. With no window but with internal heating adequate to maintain the
lens at 7°C the pressure and temperature effects cancel, with residuals of less
than one micron. While this is obviously the most extreme of the four lenses
investigated it emphasizes the need for knowledge of the flight environments
which affect the camera.
The calibrated focal length investigation shows changes that vary with the
three environments investigated, and which may exceed the quoted calibration
values of accuracy. Meier calls attention also to the fact that the "alter-
nations are by no means proportional to the focal length."
The changes in focus results mainly from reduction in air pressure as flying
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