ASTRO:
     type=emission nebula
     mag=2.2
     const=Cygnus
     dist=2200 ly
     size=96 ly
IMAGE:
     location=EB Driveway
     BrtlCls=4
     moon=22%
     exposure=CMOS OSC: 89x300s (7.4h), G100
     color palette=HOO
EQUIPMENT:
​     optics=ES102CF APO / Starizona "L" 0.65x rdcr, FL(eff.)=464mm, f(eff.)/4.55
     camera=ZWO ASI2600MC-Pro
     filter=Optolong L-eXreme DNB
     mount=Celestron AVX EQ
     guiding=Orion 60x240mm, ZWO ASI224MC
SOFTWARE:
     acquisition=Stellarium, NINA, PHD2
     processing=PixInsight (RCAstro), Photoshop (WebSharpPro), LrC

Sh2-119 is a fascinating emission nebula in the constellation Cygnus.  It is located about 2 degrees east of the North America nebula, surrounding a very bright star, 68 Cygni, which has a magnitude of 5.0; highlighted here with an artificial starburst.  By popular consensus of the astronomical community, the nebula has acquired the common name, "The Clam Shell" nebula; due largely to its vague resemblance to a large, open clam shell encircling 68 Cygni which occupies the place of a pearl at the center of the open shell.  Lying some 2200 light years away, this super-sized mollusk is actually a glowing cloud of gas and dust, illuminated mostly by electromagnetic radiation (very intense light) released from 68 Cygni, but also by contributions from other nearby stars.  The bright, blue-white stars within Sh2-119 are responsible for ionizing the gas within the nebula, causing it to, in-turn, emit light at several different specific wavelengths.  The most prominent and easily captured wavelengths by amateur astrophotographers are the Red of hydrogen-alpha (Hɑ), and the Blue of oxygen-III (OIII); both of which are very plentiful in this object.

Like many other nebulae, Sh2-119 is a reminder of the incredible power of the universe.  The stars within the nebula are born out of clouds of dust and hydrogen gas as they become compressed under the weight of their own gravitational forces.  As they age they build new atomic elements through the process of nuclear fusion.  Then once these stellar fusion reactors exhaust their nuclear fuel, they release their newly formed material back into space, seeding the formation of new stars; and more importantly, new planets.

Sh2-119 was first catalogued by American astronomer Stuart Sharpless in his now famous "Catalogue of H-II Regions", which he developed while stationed at the U.S. Naval Observatory near Flagstaff, AZ.  Using the detailed photographic data gathered in the Palomar Observatory Sky Survey ("POSS") between 1953 and 1958, Dr. Sharpless published his work in two (2) releases, the first in 1953 containing 142 nebulae, and the 2nd ("Sh2") in 1959 containing those plus the remainder of a total of 313 nebulae.  He described the Clam Shell as a large, bright object, crossed by several areas of dark dust resulting in its distinctive and formative texture and shape.  Dr. Sharpless died in 2013 leaving an indelible mark on Astronomical Science, and on the hobby of Amateur Astronomy.﻿
IMAGER'S COMMENTS:For all intents and purposes, this DSO appears to be in the early stages of developing a "donut hole" at its center.  Much like its cousins, C49 the "Rosette" nebula,  and IC1396 the "Elephant Trunk" nebula both of which are further along in their evolutionary journey, the Clam Shell appears to be in the process of becoming hollowed-out due to the effect of erosion caused by powerful stellar winds underway at its core.  We obviously won't get to see if this prediction comes true; because, it likely won't be fully realized until millions of years from now.  But with that said, it's wonderful to be engaged in a hobby where one can actually see God's creative processes at work, and use the gifts He gave us to see, explore, and wonder.

260720 - Sh2-119 "Clam Shell" nebula