Science and worldviews in the classroom: Joseph Priestley and photosynthesis

This paper elaborates on the life and publications of Joseph Priestley, the eighteenth-century polymath. The paper outlines his particular place in the European Enlightenment; it stresses the importance of philosophy and worldview in his scientific work on pneumatic chemistry, the composition of air, and his discovery of the process of photosynthesis (or the `restoration of air` as it was called at the time); finally the paper indicates ways in which Priestley`s work on photosynthesis can be utilised in the school classroom to advance the understanding of scientific subject matter, to promote an understanding of the nature of scientific procedure and methodology, and finally to evaluate some basic tenets of the European Enlightenment that Priestley so passionately advocated

Overview of the DESI Legacy Imaging Surveys

The DESI Legacy Imaging Surveys (http://legacysurvey.org/) are a combination of three public projects (the Dark Energy Camera Legacy Survey, the Beijing–Arizona Sky Survey, and the Mayall z-band Legacy Survey) that will jointly image ≈14,000 deg2 of the extragalactic sky visible from the northern hemisphere in three optical bands (g, r, and z) using telescopes at the Kitt Peak National Observatory and the Cerro Tololo Inter-American Observatory. The combined survey footprint is split into two contiguous areas by the Galactic plane. The optical imaging is conducted using a unique strategy of dynamically adjusting the exposure times and pointing selection during observing that results in a survey of nearly uniform depth. In addition to calibrated images, the project is delivering a catalog, constructed by using a probabilistic inference-based approach to estimate source shapes and brightnesses. The catalog includes photometry from the grz optical bands and from four mid-infrared bands (at 3.4, 4.6, 12, and 22 μm) observed by the Wide-field Infrared Survey Explorer satellite during its full operational lifetime. The project plans two public data releases each year. All the software used to generate the catalogs is also released with the data. This paper provides an overview of the Legacy Surveys project