The use of charge coupled devices in astronomical speckle imaging

This research consists of a theoretical and experimental evaluation of charge coupled devices (CCDs) for use in astronomical speckle imaging. Speckle imaging is a technique for removing atmospheric blurring from ground based telescope images. Imaging performance was quantified by deriving the signal to noise ratio (SNR), including CCD readout noise, of the power spectrum and Knox-Thompson product. To verify theoretical SNR calculations, an advanced CCD camera system was built and characterized. With noise of 7.2 electrons/pixel rms at 1 Mpixel/sec, this is presently the lowest noise, high speed CCD camera for astronomical imaging. Ground based telescope observations at various light levels were obtained with the newly developed system. The telescope data validated theoretical predictions and CCDs were found to be effective speckle imaging detectors over a wide range of observational conditions. Comparisons were made between CCDs and photon counting cameras based on SNR calculations, quantum efficiency and maximum count rate. Appropriate operating regions were defined graphically for each camera.