... Spherical aberration, coma, and astigmatism are also easily observed using the star test. ... Off-axis images are complex. ... Fig. ... Diffraction by a circular aperture as a function of defocus for no aberration Airy Disk 1 wave defocus Less than 1 wave defocus Fig. ... Diffraction by a circular aperture as a function of defocus for third-order spherical aberration Paraxial Focus Small distance inside paraxial focus Moderate distance from marginal focus Immediate neighborhood of marginal focus Fig...

... Phase Diversity Imaging: Real Time Correction of the Atmosphere and Telescope . Dr. Robert A. Gonsalves . ... Join us this month for what promises to be an engaging talk by Dr. Robert A. Gonsalves, “Phase Diversity Imaging: Real Time Correction of the Atmosphere and Telescope.” Phase diversity imaging uses multiple images of an object to combat the deleterious effect of the changes in the atmosphere and telescope. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

... Gravity data reflect changes, related to the groundwater redistribution, ice melting, and precipitation accumulation. ... We apply Multichannel Singular Spectrum Analysis (MSSA, or extended EOF) technique to filter GRACE data and separate the principal components (PCs) of different periods. We performed data averaging over the large river basins of Russia. ... Fig 1. ... MSSA is a promising method for GRACE data processing, de-striping, filtering, and Principal Components (PCs) separation. ...

University Satellites and . Space Science Education . ... It is necessary to select a topic interesting from scientific point of view and simple enough to allow students understand and participate in all stages of experiment from measurements via data analysis to physical inference. ... Solar modulation effects and physical characteristics and analysis of the major solar events are possible only by joining data from space-born and surface particle and radiation detectors. ...

... Multiexposition 34 images Sun 1/1000 sec f/22 and 1 image background. ... It shows position of the Sun on the sky in the same time of a day during one year. Analemma - a trace of the annual movement of the Sun on the sky - is well known among experts of sun-dials and old Earth's globes as a diagram of change of seasons and an equation of time. ... Previously, the position of the Sun on the sky was calculated with computer as well as optimal moments of time for taking each of the exposures. ...