Hubble's Planetary Nebula Gallery. A View of NGC 3918

NGC 3918 is in the constellation Centaurus and is about 3, 000 light-years from us. Its diameter is about 0.3 light-year. It shows a roughly spherical outer envelope but an elongated inner balloon inflated by a fast wind from the hot central star, which is starting to break out of the spherical envelope at the top and bottom of the image.