The Cat’s Eye nebula, also known as NGC 6543, is a planetary nebula in the Draco constellation and is about 3300 light years from Earth. It is one of the most complex nebulae known. High resolution observations from the Hubble space telescope reveal remarkable structures like knots, jets, bubbles and sinewy arc features. At the center of the nebula there is a bright, hot star. Around 1000 years ago, this star lost its outer envelope and produced the nebula. The Cat’s Eye nebula was discovered in mid-February, 1786 by William Herschel. Also, it was the first nebula whose spectrum was explored by an amateur astronomer named William Huggins. The results of his investigation proved that planetary nebulae consist of hot gases, but not stars. Currently, nebula have been observed across the full electromagnetic spectrum, from far infrared to X-rays. Modern studies have revealed several mysteries about the nebula. The intricate structure may have been caused by materiel from a central binary star, but there is no concrete evidence of the companion star. Hubble Telescope observations revealed a number of faint rings around the Cat’s Eye. These rings are spherical shells ejected by the central star in the distant past. No one seems to be able to figure out the mechanism of those past ejections. The Cat’s Eye nebula is a well-studied planetary nebula. It is fairly bright with a magnitude of 8.1. It has a high surface brightness. The constellation is situated at right ascension 17h 58 m 33.4 s and declination +66°37’59?. The Eye’s high declination means it is easily observable from the Northern Hemisphere. NGC 6543 is almost exactly in the direction of the North Ecliptic Pole. The bright inner nebula itself is rather small. The major axis of the inner ellipse is 16.1 arcseconds. The distance between the condensations is 24.7 arcseconds. It has an extended halo of matter that the creating star ejected during its red giant phase. This halo extends over a diameter of about 5 arcminutes. The Cat’s Eye really covers a nice chunk of the galaxy.
source: Dark Matter