A large number of planetary nebulae can be found within the NGC and IC catalogs and are available elsewhere on this site (see here). As illustrated by the image below, planetary nebulae are beautiful objects to look at thanks to the glowing and colourful gaseous shrouds which make their planetary appearance and colouration possible as a result of stars having exhausted their nuclear material and having reached the last stages of their life. Some of the more exotic planetary nebulae include the Cat's Eye (NGC 6543), the Saturn Nebula (NGC 7009), the Ghost of Jupiter (NGC 3242) and the Owl Nebula (M97).

George Abell's examination of the Palomar Observatory Sky Survey in the mid 1960's yielded 86 planetary nebulae which have proven to be an observer's dream challenge, for many of these celestial objects are not only very faint in magnitude even under very dark skies but are also relatively large with dimensions often measured in minutes in lieu of seconds. Later analysis of Abell's catalog revealed that at least four of these objects, namely Abell 11, 32, 76 and 85, are not planetary nebulae at all. For the avid observer, an O-III filter is highly recommended in order to have any hope of visually detecting these elusive wonders. Abell's planetary nebulae have been classified under a web page of their own on this site (see here).

Note: NGC 6781 in Aquila is a relatively large planetary nebula spanning over 2' in apparent diameter. However, it is quite dim with a mean surface brightness of only mag 13.2 and with a central star of mag 15.0. As indicated by the image below, this planetary nebula has an irregular outer disk with one half brighter than the other half. NGC 6781 was discovered by William Herschel in 1788.