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A large wide-field telescope and camera with optical throughput over 200 m^2 deg^2 -- a factor of 50 beyond what we currently have -- would enable the detection of faint moving or bursting optical objects: from Earth threatening asteroids…
The PHOT (Portable High-Speed Occultation Telescope) systems were developed for the specific purpose of observing stellar occultations by solar system objects. Stellar occultations have unique observing constraints: they may only be…
For the majority of optical observing programs, the sky brightness provides the fundamental limit to signal detection such that the scientific feasibility is largely dictated by the moon phase. Since most observatories do not have the…
We analyze an intensity interferometry measurement carried out with two point-like detectors facing a distant source (e.g., a star) that may be partially occluded by an absorptive object (e.g., a planet). Such a measurement, based on the…
We present different methods used to identify high redshift (z>5) objects in the high-magnification regions of lensing galaxy clusters, taking advantage of very well constrained lensing models. The research procedures are explained and…
Detecting compact objects by means of their gravitational lensing effect on an observed companion in a binary system has already been suggested almost four decades ago. However, these predictions were made even before the first observations…
We present a new determination of the surface brightness of our Galaxy at the Solar Neighbourhood as observed from outside the Galaxy. We rely on various existing optical and infra-red surveys to obtain a multiwavelength estimate. On the…
Light Echoes (LEs) are the reflections of astrophysical transients off of interstellar dust. They are fascinating astronomical phenomena that enable studies of the scattering dust as well as of the original transients. LEs, however, are…
As we enter the era of TESS and JWST, instrumentation that can carry out radial velocity measurements of exoplanet systems is in high demand. We will address this demand by upgrading the UC Lick Observatory's 2.4-meter Automated Planet…
The Kuiper belt objects (KBOs) exhibit an orbital clustering of the outer planets lying at perihelion distances larger than Neptune and semimajor axes greater than 150 AU from the Sun. This implies a hitherto unknown dynamical mechanism to…
Existing methods for obtaining flat field rely on observed data collected under specific observation conditions to determine the flat field. However, the telescope pointing and the column fixed pattern noise of the CMOS detector change…
The plethora of space-borne and ground-based observatories has provided astrophysicists with an unprecedented volume of data, which can only be processed at scale using advanced computing algorithms. Consequently, ensuring the quality of…
The major cornerstone of future ground-based astronomy is imaging and spectroscopy at the diffraction limit using adaptive optics. To exploit the potential of current AO systems, we have begun a survey around bright stars to study…
Nighttime monitoring of the aerosol content of the lower atmosphere is a challenging task, because appropriate reference natural light sources are lacking. Here we show that the anthropogenic night sky brightness due to city lights can be…
More than 450 exoplanets are known and this number increases nearly every day. Only a few constraints on their orbital parameters and physical characteristics can be determined, as most exoplanets are detected indirectly. Measuring the…
We apply the sky brightness modelling technique introduced and developed by Roy Garstang to high-resolution DMSP-OLS satellite measurements of upward artificial light flux and to GTOPO30 digital elevation data in order to predict the…
This year, a second generation of coronagraphs dedicated to high-contrast direct imaging of exoplanets is starting operations. Among them, SPHERE, installed at the focus of the UT3 Very Large Telescope, reaches unprecedented contrast ratios…
We consider the possibility of detecting and tracking the hypothesized Planet 9 or other unknown planetary-mass distant solar system members, generically called Planet X, with a combination of CMB and optical imaging surveys. Planets are…
Microlensing is generally studied in the geometric optics limit. However, diffraction may be important when nearby substellar objects lens occult distant stars. In particular the effects of diffraction become more important as the…
High-resolution N-body simulations of dark matter halos indicate that the Milky Way contains numerous subhalos. When a dark matter subhalo passes in front of a star, the light from that star will be deflected by gravitational lensing,…