Nebulas

NGC 2372

NGC 2371-2 is a dual lobed planetary nebula located in the constellation Gemini. Visually, it appears like it could be two separate objects; therefore, two entries were given to the planetary nebula by William Herschel in the "New General Catalogue", so it may be referred to as NGC 2371, NGC 2372, or variations on this name.

L = 12* 1200 sec. bin1, RGB = 10 * 900 sec. bin2, HaOIII = 8* 1200 sec. bin2, in the eath filters.

Total time - 16 hours.

Pixinsight 1.8, Lightroom.

NGC 2372

M 97

The Owl Nebula (also known as Messier 97,M97 or NGC 3587) is a planetary nebula located approximately 2,030 light years away in the constellation Ursa Major. It was discovered by French astronomer Pierre Méchain on February 16, 1781. When William Parsons, 3rd Earl of Rosse, observed the nebula in 1848, his hand-drawn illustration resembled an owl's head. It has been known as the Owl Nebula ever since.

The nebula is approximately 8,000 years old. It is approximately circular in cross-section with a little visible internal structure. It was formed from the outflow of material from the stellar wind of the central star as it evolved along the asymptotic giant branch. The nebula is arranged in three concentric shells, with the outermost shell being about 20–30% larger than the inner shell. The owl-like appearance of the nebula is the result of an inner shell that is not circularly symmetric, but instead forms a barrel-like structure aligned at an angle of 45° to the line of sight.

The nebula holds about 0.13 solar masses of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur; all with a density of less than 100 particles per cubic centimeter. Its outer radius is around 0.91 ly (0.28 pc) and it is expanding with velocities in the range of 27–39 km/s into the surrounding interstellar medium.

L = 18 * 1200 sec. bin1, RGB = 10 * 900 sec. bin2, HaOIII = 10 * 1200 sec. bin2, in the each filters.

Total time - 20 hours

Pixinsight 1.8 and Lightroom.

M 97

NGC 2392

The Eskimo Nebula (NGC 2392), also known as the Clownface Nebula or Caldwell 39, is a bipolar double-shell planetary nebula (PN). It was discovered by astronomer William Herschel in 1787. The formation resembles a person's head surrounded by a parka hood. It is surrounded by gas that composed the outer layers of a Sun-like star. The visible inner filaments are ejected by a strong wind of particles from the central star. The outer disk contains unusual light-year-long filaments.

The nebula was discovered by William Herschel on January 17, 1787, in Slough, England. He described it as "A star 9th magnitude with a pretty bright middle, nebulosity equally dispersed all around. A very remarkable phenomenon." NGC 2392 WH IV-45 is included in the Astronomical League's Herschel 400 observing program.

NGC 2392

IC 434

IC 434 is a bright emission nebula in the constellation Orion. It was discovered on February 1, 1786 by William Herschel. The Horsehead Nebula is a dark nebula silhouetted against it.

The Horsehead Nebula is one of the most recognizable of deep sky objects by virtue of its distinct resemblance to its namesake. It is certainly the best known example of a dark nebula. The Horsehead is also known by the less descriptive Barnard 33. The nebula is a classic dark nebula and may only be seen because it is silhouetted against the very faint glow of IC 434, a reef of tenuous emission nebulosity.

Burnhams Celestial Handbook reports that the Horsehead was first detected in photographs in 1889 by E. Pickering. Burnhams also reports that the significance of this object was not immediately recognized. Early descriptions refer to this object as a "bay" or a gap in IC 434. It appears that E. Barnard was the first to recognize that it was actually obscuring light from behind.

The Horsehead is believed to a dense cloud of tiny interstellar grains of dust that blocks the light of the emission nebula IC 434 and stars behind. While dark nebula are generally invisible (except of course where back lit as in the case of the Horsehead), their dust grains very effectively absorb light and ultraviolet radiation and then re-radiate this energy at infrared wavelengths.

The Horsehead nebula is one of the most difficult of visual objects and requires dark skies and large aperture to view.

IC 434