Improved Analysis of STEVE Photographs

Abstract:

We present a new approach for the analysis of high-resolution digital camera photographs taken by photographers who have fortuitously been able to capture rare events such as the glowing sky phenomenon known as STEVE. This method is especially effective with a time lapse series of images of the night sky taken under constant camera settings with a steady pointing. Stars, planets and satellites seen in such images can be used to determine precise and accurate registration of camera pixels to coordinates of angular altitude and azimuth. The location of satellites in the image enables precise and accurate synchronization of the images. We apply these techniques to the series of photographs of STEVE taken on 25 July 25 2016. We confirm the altitude structure previously found for STEVE. We extract novel information about the energy spectrum of the particles responsible for the production of STEVE luminosity in this particular event.

The attached figure shows an example of a composite panoramic image (using our approach) from a series of photographs taken from a site near Regina Saskatchewan together with contemporaneous images from three nearby All Sky Imagers. Superimposed on these images in green is a grid of magnetic field line segments extending from a lower altitude of 190 km to an upper altitude of 250 km, and extending over a range of magnetic longitudes from 24° to 62° West. The high-resolution of the digital camera photographs enables the extraction of fine details of the three-dimensional structure of the STEVE luminosity visible in this figure. From this detailed structure, a great deal of novel information regarding the nature of STEVE can be extracted.