California Nebula NGC1499

The California Nebula (NGC 1499) is an emission nebula located in the constellation Perseus Its name comes from its resemblance to the outline of the USA State of California in long exposure photographs. It is almost 2.5° long on the sky and, because of its very low surface brightness, it is extremely difficult to observe visually. It can be observed with a Halfa filter (isolates the Halfa line at 656 nm) or Hbeta filter (isolates the Heta line at 486 nm) in a rich-field telescope under dark skies. It lies at a distance of about 1,000 light- years from Earth. Its fluorescence is due to excitation of the Hbeta line in the nebula by the nearby prodigiously energetic O7 star, Xi Persei. The California Nebula was discovered by E.E. Barnard in 1884.