Planetary Nebulae

The Eskimo Nebula (NGC 2392): Clownface Nebula or Caldwell 39

It is a bipolar double-shell planetary nebula, surrounded by gas that was once the outer layers of a Sun-like star. The inner filaments are expelled by a strong wind made up of particles from the central star while the outer disk contains unusual light-year-long filaments.

It was discovered by astronomer William Herschel in 1787.

NGC 2392 lies more than 2,870 light-years away and is visible in the constellation of Gemini.

The Helix Nebula: The Helix, NGC 7293

Large planetary nebula is similar in appearance to the Cat's Eye Nebula and the Ring Nebula, whose size, age, and physical characteristics are similar to the Dumbbell Nebula. It only varies in its comparative proximity and appearance from the equatorial viewing angle.The Helix Nebula has sometimes been referred to as the "Eye of God", as well as the "Eye of Sauron" based on the Lord of the Rings series.

Discovered by Karl Ludwig Harding in the 1800s, of all the bright planetary nebulae it is one of the closest to the Earth. The estimated distance is about 215 parsecs or 700 light-years.

It is located in the constellation Aquarius.

Little Ghost Nebula: NGC 6369

It is located in the constellation Ophiuchus and was discovered by William Herschel

Round and planet-shaped, the nebula is also fairly faint. The former white dwarf star, seen near the center in this photo, radiates strongly at ultraviolet wavelengths and is what causes the nebula's glow. The main ring structure is about a light-year across and the glow from ionized oxygen, hydrogen, and nitrogen atoms are colored blue, green, and red respectively.

The Owl Nebula: Messier Object 97 (M97) and NGC 3587.

It was discovered by French astronomer Pierre Méchain on February 16, 1781, though it wasn't until William Parsons, 3rd Earl of Rosse observed the nebula in 1848, and his hand-drawn illustration resembled an owl's head, that it was named the Owl Nebula.

It is located approximately 2,030 light years away in the constellation Ursa Major.

The nebula is approximately 8,000 years old and is circular in cross-section with a little visible internal structure. It is arranged in three concentric shells, with the outermost shell being a bit larger than the inner shell. The owl-like appearance of the nebula comes from the inner shell that is not circularly symmetric, but forms a barrel-like shape.

Its outer radius is around 0.91ly (0.28pc) and it is still expanding.

The nebula was imaged by the Hubble Space Telescope in the 1990s.

Minkowski 2-9: M2-9, Minkowski's Butterfly, the Wings of a Butterfly Nebula or just Butterfly Nebula, and Twin Jet Nebula

Discovered by Rudolph Minkowski in 1947 and is located about 2,100 light-years away from Earth in the constellation Ophiuchus.

It is a bipolar nebula which takes the peculiar form of twin lobes of material that emanate from a central star. Astronomers have dubbed this object as the Twin Jet Nebula because of the jets believed to cause the shape of the lobes. Its form also resembles the wings of a butterfly. The primary component of this nebula is the core of its star that has reached the end of its main-sequence life cycle, ejecting most of its outer layers and becoming a red giant, and is now in the process of contracting into a white dwarf.

The Cat's Eye Nebula: NGC 6543

Relatively bright planetary nebula in the northern constellation of Draco, and was discovered by William Herschel on February 15, 1786. It was the first planetary nebula whose spectrum was investigated by the English astronomer William Huggins, demonstrating that planetary nebulae were gaseous and not stellar in nature.

Its small bright inner nebula covers an average of 16.1 arcsec, with the outer prominent condensations about 25 arcsec. Deep images reveal an extended halo about 300 arcsec across, that was most likely ejected by the central star during its red giant phase.

The Cat's Eye nebula, given in some sources, lies about three thousand light-years from Earth.