Planetary auroral imaging

Abstract

The interaction of the solar wind and the Earth magnetosphere cause auroras. The energetic electrically charged particles, mostly electrons, accelerate along the Earth magnetic field lines into the upper atmosphere, where they collide with gas atoms, causing them to emit light. Some planets also have auroral emission in their characteristic environment. The Jovian magnetosphere is the largest magnetosphere of the solar system and its system is different from the Earth. The auroras on Jupiter can be studied with high sensitivity and resolution by the Hubble Space Telescope (HST) Ultraviolet (UV) and far-ultraviolet Space Telescope Imaging Spectrograph (STIS) and Advanced Camera for Surveys (ACS) instruments. I present the planetary auroral imaging techniques, geometrical transformation and subtraction the airglow model, which can be used as a pre-processing to the image before further process by the VOronoi Image SEgmentation (VOISE) algorithm. VOISE is a dynamic and self-organising algorithm which creates a partition of an image pixel into Voronoi diagram (VD) regions according to prescribed homogeneity criteria. The Jovian auroral image was selected from the APIS database. Using a planetary model, the geometric transformation was performed to get the polar projection, build the airglow model and subtract it from the original to make a clear auroral representation in the two dimensional image.