ScienceDownEast | ScienceDownEast Astrophotography | Nebulae | M16 Eagle Nebula | M16 Eagle Nebula
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M16, the Eagle Nebula (IC 4703) in the constellation Serpens Cauda. The cluster was discovered by Philippe Loys de Cheseaux in 1745-1746, who made no mention of the nebula. Charles Messier independently rediscovered the cluster in 1764, and described its stars as "enmeshed in a faint glow", suggesting that he discovered the nebula as well. The Herschels apparently did not perceive the nebula, so their catalogs (and consequently the NGC) only describe the cluster. The nebula was probably first photographed by E.E. Barnard in 1895, or by Isaac Roberts in 1897. From Roberts's finding, the nebula was added to the second Index Catalog in 1908 as IC 4703, "with cluster M 16 involved". M 16 is found rather easily, close to Serpens Cauda's borders with Scutum and Sagittarius. Starting from Altair (α Aquilae), follow δ and λ Aql to Gamma Scuti; M 16 is about 2-1/2° west of this star. The Omega Nebula (M 17) is 2° SW of γ Sct. With an overall visual magnitude of 6.4, and an apparent diameter of 7', the Eagle Nebula's star cluster is best seen with low power telescopes. The brightest star in the cluster has an apparent magnitude of +8.24, easily visible with good binoculars. A 4" scope reveals about 20 stars in an uneven background of fainter stars and nebulosity; three nebulous concentrations can be glimpsed under good conditions. Under very good conditions, suggestions of dark obscuring matter can be seen to the north of the cluster.
Total image time was 40 minutes.
| Exposure | 4 x 10 min. | |||||||||
| Gain | 100 | |||||||||
| Camera | ToupTek ATR2600C [6224 x 4168] | |||||||||
| Optics | 120mm Skywatcher Esprit on a Proxisky UMi20S Strain Wave mount | |||||||||
| Guiding | ToupTek GPM462M using Phd2 with a 400mm guide scope. Average 20 min sub GuideRMS ranged from 0.4 to 0.6 using 0.5 sec exposures. | |||||||||
| Controller | Kstars on MeLe Quieter 4C | |||||||||
| Filter | Triad Quad Ultra | |||||||||
| Location | St. Croix Observatory, Nova Scotia. | |||||||||
| Date | 2025-09-21 | |||||||||
| Processing | Processed in PixInsight. | |||||||||
| PixInsight Processing |
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