Lights in the sky
The AZURE mission (see my previous uploads) used sounding rockets to release these glowing tracer clouds in the upper atmosphere, from around 100km to up to 250km altitude. Observers at the ground sites (like me) then use optical instruments - which are mostly off-the-shelf dSLR cameras - to track the way the clouds move over the next ~30 minutes. This allows investigators to learn about the winds and magnetic fields at these altitudes.
As a bonus, it also looks spectacular.