240909 - M17 "Omega" nebula
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click image to enlarge
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ASTRO:
type=Emission nebula; mag=6.0 const=Sagittarius dist=6000 ly size=22 ly IMAGE: location=EB Driveway BrtlCls=5 exposure=CMOS OSC; 26x300s (2.2h), G100 palette=HOO EQUIPMENT: camera=ZWO ASI2600MC-Pro Optics=ES102 w1.0x fltnr, FL=714mm, f/7 filter=Optolong L-eXtreme duo NB mount=Celestron AVX guiding=Orion 60x240mm, ZWO ASi224MC SOFTWARE: acquisition=Stellarium, APT, PHD2 processing=PixInsight (RCAstro), Photoshop (Lumenzia), LrC |
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The Omega Nebula has been called by many names in recent years; it is also known as the Swan, Checkmark, Lobster, and Horseshoe Nebula to name a few. Catalogued as Messier 17 (or M17), and NGC 6618, it is an H-II region in the summertime constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is associated with some of the richest star fields known, located just outside the central core nucleus area of the Milky Way, encompassing the northern two-thirds of Sagittarius.
The Omega is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years across. The total mass of the nebula is estimated to be appx 800 solar masses; but, the larger cloud of interstellar matter of which it is a part is roughly 40 light-years in diameter and has a mass of appx 30,000 solar masses.
The larger star-mass is considered one of the brightest and most massive star-forming regions in our galaxy. Its local geometry is similar to the Orion Nebula of our wintertime skies, except that it is viewed from our vantage point here on Earth in edge-on orientation rather than face-on like that of Orion.
Much of the open star cluster NGC 6618 lies embedded deep inside Omega's nebulosity and causes the gases of the nebula to shine due to radiation from its hot, young, energetic stars. From recent deep, near infra-red ("NIR") exploration, scientists know the actual number of stars in the nebula is much higher than what can be seen at visible wavelengths - up to 800, consisting of appx 100 spectral type earlier than B9, and 9 of spectral type O, plus over a thousand stars in formation in its outer regions. It is one of the youngest clusters known (by astronomical standards) with an age of just 1 million years.
The Omega is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years across. The total mass of the nebula is estimated to be appx 800 solar masses; but, the larger cloud of interstellar matter of which it is a part is roughly 40 light-years in diameter and has a mass of appx 30,000 solar masses.
The larger star-mass is considered one of the brightest and most massive star-forming regions in our galaxy. Its local geometry is similar to the Orion Nebula of our wintertime skies, except that it is viewed from our vantage point here on Earth in edge-on orientation rather than face-on like that of Orion.
Much of the open star cluster NGC 6618 lies embedded deep inside Omega's nebulosity and causes the gases of the nebula to shine due to radiation from its hot, young, energetic stars. From recent deep, near infra-red ("NIR") exploration, scientists know the actual number of stars in the nebula is much higher than what can be seen at visible wavelengths - up to 800, consisting of appx 100 spectral type earlier than B9, and 9 of spectral type O, plus over a thousand stars in formation in its outer regions. It is one of the youngest clusters known (by astronomical standards) with an age of just 1 million years.