X,Y, and Z: A bird's eye view on light pollution.

The global increase in light pollution is being viewed with growing concern, as it has been reported to have negative effects ranging from the individual to the ecosystem level.Unlike movement on the ground, flying and swimming allows vertical motion. Here, we demonstrate that flight altitude change is crucial to the perception and susceptibility of artificial light at night of air-borne organisms.

The Colour of the Night Sky.

The measurement of night sky quality has become an important task in night sky conservation. Modern measurement techniques involve mainly a calibrated digital camera or a spectroradiometer. However, panchromatic devices are still prevalent to this day, even in the absence of determining the spectral information of the night sky.

Light Pollution Monitoring and Sky Colours.

The measurement of night sky quality has become an important task in nature conservation. The primary device used for this task can be a calibrated digital camera. In addition, colour information can be derived from sky photography.

Imaging and mapping the impact of clouds on skyglow with all-sky photometry.

Artificial skyglow is constantly growing on a global scale, with potential ecological consequences ranging up to affecting biodiversity. To understand these consequences, worldwide mapping of skyglow for all weather conditions is urgently required. In particular, the amplification of skyglow by clouds needs to be studied, as clouds can extend the reach of skyglow into remote areas not affected by light pollution on clear nights.

Chaos in variable stars: Topological analysis of W Vir model pulsations.

The topological characterization of chaos is applied to the irregular pulsations of a model for a star of the W Virginis type, computed with a state-of-the-art numerical hydrodynamical code. The banded W Vir attractor is found to possess an additional twist when compared to the Rossler band. It is shown that the stellar light-curve contains the same dynamical information about the attractor as the stellar radius or as the radial velocity variations.