Le Gentil 3 is a very large, dark nebula in northern Cygnus lying between the North America and Pelican Nebulae to the south, and IC 1396 in Cepheus to the north. It is rarely imaged but is visible to the naked eye from observing sites with dark skies.
Most noticeable and familiar on the image are the North America Nebula, NGC 7000, and the Pelican Nebula, IC 5070, at bottom center immediately left of Bluish-white Deneb, alpha Cygni. The reddish emission nebula to the upper left of the North America Nebula is Sharpless 2-119. In the upper left center of the image is a small, circular reddish emission nebula located at the end of a diagonal dark nebula; this is IC 5146, the Cocoon Nebula. Bluish open cluster M39 is visible at upper left center. The reddish emission nebula at upper right is the southern portion of IC 1396, which contains the Elephant Trunk nebula.
At least twenty six Barnard dark nebulae are also visible on the image, and are, from north to south, B163, B162, B160, B365, B154, B153, B151, B360, B157, B364, B164, B362, B363, B361, B351, B356, B352, B353, B345, B350, B155, B158, B159, B358, B355, and B349. It is interesting to follow the tendrils of dark dust from the Great Rift in Cygnus, anastamosing northward and coalescing into Le Gentil 3 and extending upward into Cepheus.
Canon 450D Full Spectrum at 52mm , 20.7 arcseconds/pixel, north to upper right.
Sky condition clear with skyglow of SQM 21.2 magnitudes per square arcsecond.
Calibration with dark frames of identical exposure, along with sky flats and matched dark frames. Processed in Pixinsight as follows:
AutomaticBackgroundExtraction on separate RGB planes
PhotometricColorCalibration
MultiscaleLinearTransform of chrominance
HistogramTransformation
TGVDenoise
CurvesTransformation
Cropped and converted to JPG for upload. Rotated to a North to upper right orientation.
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