... Astrofisica de Canarias ) Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky . ... Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows emission from nitrogen atoms as red and oxygen atoms as green and blue shades. ... While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years. ...