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	WeightedBatchPreprocessing Script BlurXTerminator GraXpert SpectrophotometricColour Calibration NoiseXTerminator StarXTerminator Generalized Hyperbolic Stretch on both the stars and starless images HDRMultiScaleTransform on Starless PixelMath to recombine the images

Date: April 14, 8151 ]]> https://sciencedowneast.com/zenphoto/index.php?album=Nebulae/M16-Eagle-Nebula&image=M20-Eagle-Nebula.jpg Mon, 22 Sep 2025 18:55:51 -0300 https://sciencedowneast.com/zenphoto/index.php?album=Nebulae/M16-Eagle-Nebula&image=Exp-300.00s_FILTER-NoFilter_starless-DeNoiseAI-severe-noise.jpg

Click on the image to enlarge.

Click on the image to enlarge.

Click on the image to enlarge.

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A total of 4.9 hours exposure.

Exposure	59*300 sec
ISO	800
Camera	Nikon Z7 [8856 x 5504]
Optics	Skywatcher Esprit 120mm Refractor
Filter	Radian Triad Ultra Quad-Band Narrowband Filter
Location	Lower Sackville, Nova Scotia.
Date	2020-06-19
Processing	Processed in PixInsight and Lightroom.

Date: March 26, 2025 ]]> https://sciencedowneast.com/zenphoto/index.php?album=Nebulae/M16-Eagle-Nebula&image=M16_Eagle_Nebula_EXPTIME_300_integration_DBE1.jpg Sun, 21 Jun 2020 08:06:25 -0300