This Hubble image is of the Red Spider Nebula - one of the targets of the ISO observations.

Hubble observations have revealed huge waves sculpted in the Red Spider Nebula. This warm and windy planetary nebula harbours one of the hottest stars in the Universe and its powerful stellar winds generate waves 100 billion kilometres high - intimidating for even the bravest space surfers. The Red Spider Nebula, NGC 6537, is a striking 'butterfly' or bipolar (two-lobed) planetary nebula. Planetary nebulae are the glowing embers of ordinary stars, such as our Sun. At the end of their lives these stars expel most of their material into space, often forming a two-lobed structure as in the case of the Red Spider. This NASA/ESA Hubble Space Telescope image shows that the gas walls of the two lobed structures are not at all smooth, but rather are rippled in a complex way. These waves are driven by stellar winds radiating from the hot central star, much as a wind passing over a lake can generate waves on the water.