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QC 351 A7 no. 20 / The control system described in this thesis was designed to automatically guide the position of photographic plates during long exposures of astronomical objects. The system senses the position of the guide star which is being used as a position reference, and moves the photographic plate in two orthogonal directions in order to maintain a constant position of the image of the astronomical object on the photographic plate. The system was designed to have a bandwidth of 35 radians per second in order to track the worst case image excursions due to atmospheric turbulence and telescope motion. The closed loop transient response of the system was determined from considerations of final image resolution of the photographic plate. Due to the necessity of guiding on stars of unknown brightness the system incorporated an automatic gain control loop within the forward control loop and was made unconditionally stable by high order feedback. In operation on the Steward Observatory telescopes, the system has made a significant increase in photographic plate resolution over manually guided plates.

This creative project presents a comprehensive and detailed guide to the building of inexpensive studio lighting equipment. The projects include simple equipment such as backgrounds, snoots and scrims to more specialized equipment like the glassware table and softlight box.Each project includes figures and instructions for building the equipment. At the end of each project are examples of the effects of each piece of equipment in a photographic situation.Also included is a list of photographic data on how each of the photographs was taken.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / The successful control of a three-degree-of-freedom gyroscope is presented for the application of steering and stabilising a platform mounted underneath an airship. The end goal is to stabilise a camera for earth observation purposes. The development of the necessary electronics, sensors and actuators along with the hardware and software to interface these components are presented. This include DC drives, torque control systems for the gimbal motors and a speed control system for the gyroscope as well as platform angle and angular rate sensors. A mathematical model for the gyroscope, based on Euler's equations of motion, is presented. Non-linear simulations are performed and compared to measurements of the plant's behaviour to step torque commands to determine the parameters of the gyroscope. Pole placement and LQR optimal control methods are considered in the design of a MIMO controller to steer the platform in the elevation plane, along with a PI controller to steer the platform in the azimuth plane. Ground tests display the success of the steering controllers.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2007 / The lack of a standardized lighting instrument to be used in conjunction with existing photographic methods to document rock art, is a problem experienced in archaeological circles. Through interviews with archaeologists and an investigation into existing photographic methods concerning the photographing of rock art, a demand for a portable and modular lighting instrument was confirmed. The aim of this study, then, was to develop a prototype lighting instrument to fill this void. The design and manufacture of the modular lighting instrument entailed the harnessing of the technological advances made in the field of rapid prototyping. A brief overview of the San/Bushmen of Southern Africa is given to stress the importance of this study and to emphasise the importance of the art of the Bushman in our collective art heritage. An overview of the documenting of rock art and therewith an investigation into documented works of rock art and rock engravings by the San/Bushmen serves as a point of departure for the present inquiry. Tests undertaken with the modular lighting instrument, and a comparison of the results so obtained with existing photographic methods, showed that with the use of the modular lighting instrument, an improvement in illumination, rock-face texture and colour contrast in the images was obtained. The modular lighting instrument helps to create and regulate a suitable lighting environment irrespective of natural lighting circumstances and environments. It produces better results when it comes to documenting rock art in comparison to existing methods of documentation. Continued study for the development of the modular lighting instrument is recommended in order to produce more constant results.