A Collection of Bipolar Planetary Nebulae
Beautifully symmetrical bipolar planetaries are among the most spectacular objects imaged by the Hubble Space Telescope and other large instruments. In 1987 planetary-nebula specialist Bruce Balick coined the term "butterfly nebulae" to cover their incredible diversity of shapes and color. Researcher Sun Kwok's latest book, Cosmic Butterflies, presents numerous images of the sky's most visually appealing and dynamically interesting bipolar planetaries. Many are fairly large and have high surface brightnesses, making them especially appealing for amateur astronomers. With the use of a nebula filter and high magnification, a diligent observer may even be able to discern structure often hidden by conventional photography.