Observing Small-Scale Ionospheric and Upper Atmospheric Structure with Low-Light Optics

Imaging of optical emissions in aurora and airglow has been one of the few ways of determining the spatial structure and dynamics of the ionosphere and upper atmosphere. But observations are inherently limited by the integration time required for measurement of low-intensity emissions and the dynamic motion of the upper atmosphere and ionosphere during that integration time. The low-intensity short-temporal-scale corner of the intensity/dynamics parameter space is expected to contain a wealth of information on turbulence, irregularities, and wave structures, but has been sampled only with non-imaging photometer-type systems and is ripe for exploration as imaging technologies improve and become more accessible. Typical astronomical observatories already have detectors with orders of magnitude more light collection capability than instruments typically used in aeronomy. Developing high-throughput optical systems that can take advantage of such detectors but are optimized for the wider fields of view and shorter time scales of upper atmospheric phenomena will be critical to pushing the boundaries of the parameter space. We will discuss motivations from data collected with traditional low-light imagers, describe a new system designed with a large 2" CCD detector and a very fast lens specifically to observe dynamic upper atmospheric structures, and present initial results from its operation in the field. We will also discuss opportunities and challenges in adapting astronomy systems for aeronomy studies.