We present a detailed study of the color magnitude diagram (CMD) of the dwarf spheroidal galaxy Leo I, based on archival Hubble Space Telescope data. Our photometric analysis, confirming previous results on the brighter portion of the CMD, allow us to obtain an accurate sampling of the stellar populations also at the faint magnitudes corresponding to the Main Sequence. By adopting a homogeneous...

We explore how well crowded field point-source photometry can be accomplished with Sloan Digital Sky Survey (SDSS) data. For this purpose, we present a photometric pipeline based on DoPHOT (Schechter et al. 1993), and tuned for analyzing crowded-field images from the SDSS. Using Monte Carlo simulations we show that the completeness of source extraction is above 80% to an i band AB magnitude of ...

High-accuracy Low Earth Orbit (LEO) satellite clock and orbital products are preconditions to realize LEO augmentation for high-accuracy GNSS-based positioning on the ground. There is a high correlation between orbit parameters in kinematic Precise Determination (POD) process. While future satellites planned be equipped with better clocks, benefits of modeling high-stability clocks not yet thor...

It is with great sorrow that we write about the demise of Leo Sachs, the Otto Meyerhof Professor of Molecular Biology, friend, colleague and brilliant scientist. Leo was born in Leipzig, Germany in 1924, emigrated with his family from Nazi Germany to England in 1933, and reached Israel in 1952. He began studying agricultural botany at the University of Wales, became fascinated by genetics and d...