ABSTRACT
A level frequency postulate is proposed in the context of the Onsager regression hypothesis, and is utilized to demonstrate Fourier fluctuation time between levels in an analog system composed of red and white dice. This dice system is shown to be analogous to an isolated composite system of particles through derivation of the level probability distribution. Level fluctuation time is developed as an algebraic expression involving average energy and a Gaussian parameter, with quasistatic evolution demonstrated as an integral over fluctuation time.
ABSTRACT
A deformable mirror mounted on a two-axis tilt platform can provide wavefront compensation at a single location in an adaptive optics system, resulting in a significant reduction in the number of optical components in the system and in a simplification of the alignment. However, the moment of inertia of a deformable mirror is significantly different from that of the monolithic mirror commonly mounted on a tilt platform. We report on what are to our knowledge the first experimental results of mounting a microelectromechanical deformable mirror onto a fast steering platform and the first observation that at low operating frequencies high-order deformation of the deformable mirror membrane was not recorded.
ABSTRACT
High-resolution imaging can be dramatically improved by combining a fast image stabilization system and variable aperture masking. We describe an imaging system that provides high-resolution images through an annular aperture using the unwanted low spatial frequency light for image stabilization. The annulus thickness and diameter can be selected to enhance the contribution of different spatial frequencies in the image at the expense of image exposure time.
ABSTRACT
Astronomical seeing measurements are usually made at a single wavelength and extrapolated to other wavelengths of interest using scaling laws that assume a specific energy spectrum for the atmospheric turbulence. We describe a variation of the Differential Image Motion Monitor system that provides a measure of the seeing and evaluation of the scaling law by simultaneously measuring the image motion at three different wavelengths.
