Related papers: Satellite Visibility During the April 2024 Total E…
Coronal modelling is crucial for a better understanding of solar and helio-physics. Due to the strong brightness of the Sun and the lack of white light observations of the solar atmosphere and low corona (1-1.5R$_\odot$), total solar…
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 Heliophysics Big Year was an extended year where major solar events engaged the public. It included two eclipses (annular on October 14, 2023 and total on April 8, 2024), plus solar max and the Parker Solar Probe perihelion December 24,…
Totality during the solar eclipse of 2017 traverses the entire breadth of the continental United States, from Oregon to South Carolina. It thus provides the opportunity to assemble a very large number of images, obtained by amateur…
While Transiting Exoplanet Survey Satellite (TESS) covers a considerable area of the sky during routine observations and the pointing schedule is easy to follow, it is not obvious to retrieve the current and/or predicted visibility of a…
The Steward Observatory LEO Satellite Photometric Survey is a comprehensive observational survey to characterize the apparent brightness of the Starlink and OneWeb low Earth orbit satellites and evaluate the potential impact on astronomy.…
The impact of mega-constellations of satellites in low-Earth orbit during nighttime optical observations is assessed. Orbital geometry is used to calculate the impact of stellar occultations by satellites on the photometry of individual…
Measuring photometric brightness is a common tool for characterizaing satellites. However, characterizing satellite mega-constellations and their impact on astronomy research requires a new approach and methodology. A few measurements of…
This white paper is a call for a concerted effort to support total solar eclipse observations over the next decade, in particular for the 21 August 2017 eclipse which will traverse the US continent. With the recent advances in image…
The number of planets in the solar system over the last three centuries has, perhaps surprisingly, been less of a fixed value than one would think it should be. In this paper, we look at the specific case of Vulcan, which was both a planet…
Solar eclipses, as rare astronomical events, often evoke a profound sense of wonder and awe within the human spirit. However, for ordinary people, the extremely short preparation time, a few hours of notice from friends or social media, and…
We report observations of the total solar eclipse of 14 December 2020, during which a coronal mass ejection can be see n propagating. A comprehensive set of photographs covering a high dynamic range of exposure allow to characterize its…
On large telescopes trails of MegaConstellation's satellites will appears significantly defocused because of their relatively short distance. Because of such effect their apparent surface brightness will be, under a range of conditions,…
Private space companies are increasingly commercializing near-earth space. Some estimates show that more than 100,000 satellites may orbit the Earth by 2030. This increase in the number of satellites has many consequences for science,…
Laser ranging measurements during the total lunar eclipse on 2010 December 21 verify previously suspected thermal lensing in the retroreflectors left on the lunar surface by the Apollo astronauts. Signal levels during the eclipse far…
Precise starlight positions near the sun were measured during the 21 August 2017 total solar eclipse in order to measure their gravitational deflections. The equipment, procedures, and analysis are described in detail. A portable refractor,…
This study evaluates the effect of proposed constellations -- ranging from current deployments to mega-constellations and very bright reflector concepts -- on direct trail losses, diffuse background, and scattered sky brightness. We use a…
The number of small satellites has grown dramatically in the past decade from tens of satellites per year in the mid-2010s to a projection of tens of thousands in orbit by the mid-2020s. This presents both problems and opportunities for…
SpaceX recently proposed to orbit 19,440 Starlink internet satellites at a low altitude of 350 km instead of the current 550 km. The distribution in the sky and the apparent magnitudes of these spacecraft are simulated in this paper. During…
The apparent brightness of satellites is calculated as a function of satellite position as seen by a ground-based observer in darkness. Both direct illumination of the satellite by the Sun as well as indirect illumination due to reflection…