The development and application of an astronomical imaging and photometric CCD system
The aim of the work was to acquire and develop a low cost charge coupled device (CCD) system suitable for use in undergraduate teaching. In addition its capability for providing research quality data, on selected areas of interest to the Department of Astronomy at the University of Central Lancashire, was to be assessed. Initially the principles of operation of CCD cameras were reviewed, a suitable CCD system purchased and a camera operating program developed by modification of the original software package supplied with the device. The main characteristics of the CCD were identified. Laboratory tests established the variation within the flat field, confirmed that the variation of dark current with change in ambient temperature could be predicted by a simple equation, and showed that the dark current could be reduced to approximately 0.2 counts / second (giving a noise level of 12.5 21ectrons / V t seconds ) at an ambient temperature of 4 ° C by the addition of cooling fins. Field commissioning established signal to noise levels of the system and identified the dominant source of noise arising from digitization of the on-chip amplifier. Reference charts were produced which quickly enables the expected signal to noise to be determined for an object at a given magnitude at various integration times. The limiting magnitude of the system was determined. Suitable red and blue optical filters were purchased, a filter holder fabricated, and the effective wavelength of the system calculated. One potential area of research identified was the photomeiry of active galactic nuclei. Results extrapolated from early B stars in Perseus, show that it should be possible to determine the spectral index of a 16 th R magnitude object to an accuracy of+ or - 1 unit. Further potential applications were identified and a user guide to the CCD camera was written.
Networked Digital Library of Theses and Dissertations