North America Nebula (NGC 7000) & Pelican Nebula (IC 5070)
History
On 24 October 1786 the German-British astronomer William Herschel discovered an open star cluster which he cataloged as VIII 58 (class VIII = coarsely scattered clusters of stars) which he described as «cluster of pretty large scattered stars, not very rich». In the same night he discovered a very large nebula which he cataloged as V 37 and noted: «very large diffused nebulosity, brighter in the middle, 7 or 8' long, 6' broad and losing itself very gradually and imperceptibly.» [464] Later the star cluster VIII 58 got the designation GC 4620 in John Herschels «General Catalogue» and NGC 6997 in John Dreyers «New General Catalogue». The nebula became known as NGC 7000. [313, 467] The name «North America Nebula» can be traced back to the German astronomer Dr. Max Wolf (1863-1932) because the outlines of the luminous H-II region with the dark cloud reminded him of it. [4]
42 years later, on 28 October 1828 William Herschel son John discovered another «poor , little compressed cluster» which he cataloged first as h 2094 and then as GC 4617. That cluster received the designation NGC 6996 in John Dreyers «New General Catalogue». [313, 467]
Max Wolf took a picture of this region on 1 June 1891 and discovered further nebulae that were added as IC 5067 and IC 5070. On 7 September 1899 the British astronomer Thomas Espin reported another patch of this giant emission nebula which later got the designation IC 5067. [277]
Physical Properties
NGC 7000 is a large cloud composed of glowing gas and dark dust. The western portion, which appears separated by a dark cloud, has the designation IC 5070 and is nicknamed the «Pelican Nebula» because it somewhat resembles a seated pelican, holding its long beak to its chest and looking east toward the North America Nebula. About 1.5° south of it there is another glowing nebula, which has been given the designation IC 5068.
The star Deneb (α Cygni) is traditionally considered the main source making the H-II region glow, but it is also likely that several stars in this region are doing their part. The open star cluster NGC 6997 appears in the middle of the nebula, but whether it's at the same distance is uncertain. The distance to the nebula is estimated at about 1600 light-years, which roughly corresponds to the calculated distance of the star Deneb. The star's true distance from the nebula cannot be much less than 70 light-years. The nebula itself is about 45 light-years across. [4]
| Name | RA | Dec | Type | bMag | vMag | Dim | Dreyer Description | Identification, Remarks |
|---|---|---|---|---|---|---|---|---|
| NGC 6996 | 20 56 30.0 | +45 28 24 | OCL (III2p) | 10.0 | 5 | Cl, P, lC | OCL 197, in Milky Way | |
| NGC 6997 | 20 56 30.0 | +44 39 00 | OCL (III2p) | 10.0 | 8 | Cl, P, lC, st L | OCL 197 | |
| NGC 7000 | 20 59 18.0 | +44 31 00 | EN | 4.0 | 5.0 | 120 × 100 | F, eeL, dif nebulosity | LBN 373, North America nebula |
| IC 5067 | 20 47 50.0 | +44 22 00 | EN | 8.0 | 25 × 10 | F | LBN 353, CED 183A, Pelican nebula | |
| IC 5068 | 20 50 30.0 | +42 28 42 | EN | 40 × 30 | vF | LBN 328, CED 183B | ||
| IC 5070 | 20 51 00.0 | +44 24 06 | EN | 8.0 | 60 × 50 | F, dif | LBN 350, CED 183C, Pelican nebula |
Finder Chart
The North America Nebula lies only about 3° west of the bright star Deneb (α Cygni) in the constellation Cygnus. In the months of April to November it is highest in the sky at night and can be best observed.
Visual Observation
On clear, dark nights, when the North America Nebula is at its zenith, it can be seen with the naked eye using an O-III filter. A combination of telescope and eyepiece is recommended as an observation instrument, which offers about 2° or more field of view, so that the nebula can be seen as a whole and the shape can be recognized. If the magnification is too high, you lose yourself in the areas of light and dark.