Inappropriate or excessive artificial lighting at night (“light pollution”) is increasingly recognized as having significant negative impacts on human health and natural ecosystems. The blue component of lighting is particularly concerning due to its stronger bioactivity. These harmful effects will likely increase as cities transition from traditional, yellow high-pressure sodium vapor streetlights to bluer LED streetlights. However, systematic efforts to measure and map the extent of light pollution and its changes over time are limited by few existing, appropriate resources (satellite observations provide neither high spatial resolution nor good color discrimination) and the time-intensive labor required to make widespread manual ground-based measurements.
The Adler Planetarium is embarking on a project to measure night-time artificial illumination throughout the Chicago area, first using cameras onboard high-altitude balloons, and eventually, on one or more small orbital satellites. However, it is not entirely straightforward to convert measures of upward-pointing illumination to the light pollution reflected back downwards from the sky. Therefore, it is highly desirable to obtain simultaneous measures of ground-based sky brightness along with the overhead balloon or satellite observations, and to have these measurements made at many ground locations. Therefore, there is a strong need for a robust, automated, well-calibrated sky monitor system that is straightforward to emplace and operate and capable of being scaled up to large numbers of deployed systems.
At the same time, the capabilities of such a system lend themselves to important astronomical uses, including monitoring weather conditions at automatic or remotely operated observatories, and capturing transient events like bright meteors. Multiple observations of meteors from different locations is used to triangulate their paths through the atmosphere, not only enabling the location of potential meteorite falls but also the calculation of their original orbits in space.
Objective. The initial goal is to produce a reliable camera system capable of measuring sky brightnesses and capturing videos of transient celestial phenomena. An extended but essential goal is to scale up the production of these camera systems to enable the deployment of a large network of these systems. Part of the second goal will be to identify host sites or institutions for the camera systems. They would lend themselves very well to “citizen science” type measurements and as science education resources.
Approach. Primary stakeholders will be the light pollution research community and astronomers interested in transient celestial phenomena and remote or automated observatories. Other stakeholders include science educators and possibly those responsible for the physical infrastructure and maintenance at potential host institutions. An initial approach would be to conduct a needs assessment in discussion with the stakeholders, and to determine the necessary capabilities of the All Sky Camera system. Surveys of existing literature should also be conducted to understand what similar systems have been developed in the past, and extract any learned lessons from their development and operation.
Since this project has an ambitious scope, it is envisioned that it will extend over multiple semesters. It may also be posed as a design competition between multiple simultaneous IPRO teams and other interested students and student organizations.
This project will depend heavily on experience in electrical design and engineering, optical design (including video-rate camera sensors), computer science (particularly programming of small computer systems), and user interface design. Expansion of the network and the “citizen science” component will draw on expertise in industrial/manufacturing technology, information technology and management, business, psychology, and science education.