Related papers: Optimising background-limited observing during bri…
With a sky brightness monitor in Xinglong station of National Astronomical Observatories of China (NAOC), we collected data from 22 dark clear nights and 90 lunar nights. We first measured the sky brightness variation with time in dark…
Recent weak lensing observations have pushed the use of 4 meter-class telescopes to the limits of their capabilities with exposure times exceeding several hours. The leading idea is that the surface density of faint galaxies up to very…
The illumination phase functions for Starlink Mini satellites are determined for times of twilight and darkness. Those functions are then evaluated to give apparent magnitudes over a grid of points across the sky and over a range of solar…
The sky brightness is a critical parameter for estimating the coronal observation conditions for solar observatory. As part of a site-survey project in Western China, we measured the sky brightness continuously at the Lijiang Observatory in…
Polarimetry in the far-infrared and submillimeter has been valuable in tracing magnetic fields in bright Galactic Clouds. We discuss the techniques we have developed and trends we have found in polarization vs column density, and vs…
Many spectacular polarimetric images have been obtained in recent years with adaptive optics (AO) instruments at large telescopes because they profit significantly from the high spatial resolution. This paper summarizes some basic…
The LSST survey will provide unprecedented statistical power for measurements of dark energy. Consequently, controlling systematic uncertainties is becoming more important than ever. The LSST observing strategy will affect the statistical…
Research activities during the last decade have shown the strong potential of photonic devices to greatly simplify ground based and space borne astronomical instruments and to improve their performance. We focus specifically on the…
Pulsar timing now has a rich history in placing limits on the stochastic background of gravitational waves, and we plan soon to reach the sensitivity where we can detect, not just place limits on, the stochastic background. However, the…
Polarization plays an important role in various time-domain astrophysics to understand the magnetic fields, geometry, and environments of spatially unresolved variable sources. In this paper we present the results of laboratory and on-sky…
Autonomous driving and advanced driver-assistance systems rely on a set of sensors and algorithms to perform the appropriate actions and provide alerts as a function of the driving scene. Typically, the sensors include color cameras, radar,…
We developed a Python based framework for astronomical image processing and analysis. Astronomical image loading, normalizing, stacking, and filtering processes represent visible range images from grayscale. Besides, the blending process…
The Sun may copiously produce hypothetical light particles such as axions or dark photons, a scenario which can be experimentally probed with so-called helioscopes. Here we investigate the impact of the angular and spectral distribution of…
Orbital detectors without pointing capability have to keep their field of view axis laying on their orbital plane, to observe the largest sky fraction. A general approach to estimate the exposure of each sky element for such detectors is a…
The determination of the Hubble parameter H_0 is probably one of the most important applications of quasar lensing. The method, based on the measurement of the so-called ``time-delay'' between the lensed images of distant sources, e.g.,…
We outline scientific objectives for monitoring X-ray sources and transients with wide-angle, coded mask cameras. It is now possible to instantaneously view half of the sky over long time intervals, gaining access to events of extraordinary…
Weak lensing observations have the potential to be even more powerful than cosmic microwave background (CMB) observations in constraining cosmological parameters. However, the practical limits to weak lensing observations are not known.…
This paper presents multi-filter measurements of the night sky brightness at the South African Astronomical Observatory (SAAO) in Sutherland in the presence of a bright moon. The observations cover a wide range of sky directions, lunar…
More than half of the volume of our Universe is occupied by cosmic voids. The lensing magnification effect from those under-dense regions is generally thought to give a small dimming contribution: objects on the far side of a void are…
Recently, several eclipsing millisecond pulsars have been shown to experience strong and apparent weak lensing from the outflow of their ionized companions. Lensing can be a powerful probe of the ionized plasma, with the strongest lenses…