First results from the Penn State Allsky Imager at the Arecibo Observatory

The Penn State Allsky imager (PSASI), a user-owned-public-access (UOPA) instrument installed at Arecibo Observatory (AO: 18.3 degrees N, 66.75 degrees W; altitude: 350 m a.s.l.; L = 1.43 at 300 km; dip angle: 46 degrees; geomagnetic coordinates: 29 degrees N, 5.5 degrees E), is a CCD-based high-resolution allsky optical imager that has been collecting ionospheric airglow data at night since May 2003. The computer controlled six-position filter wheel is equipped with three filters at 630 nm (red), 557.7 nm (green), and 777.4 nm (near-IR), respectively, which correspond to ionosphere-related oxygen emissions. The imager data, taken for more than 3.5 years now, is being used to study various ionospheric processes, such as mapped equatorial spread-F plumes, E-region gravity waves, among other, in conjunction with the AO incoherent scatter radar (ISR), mesosphere and lower thermosphere (MLT) metals lidar, and other instruments, including microbarographs. Data availability and quality as well as specific airglow events on both small/large time/spatial scales are examined, categorized, and made freely available at a data-server website. Our goal here is to briefly review the airglow science enabled by allsky imaging at AO, to describe the instrument and the data-collection methodology, and to present some of the significant results, including airglow events that correspond to ISR results.