Messier 17. The Omega Nebula

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Messier 17 is a bright emission nebula in the constellation Sagittarius. This nebula is often overlooked due to its closeness to Messier 16, the home to the Pillars of Creation, a more frequent astrophotographic target. It is also the birthplace of many stars and it contains, in its core, an open cluster (NGC 6618) with about 800 stars in it. Povich et al. have calculated that more than 1000 stars “are in the process of forming in the extended outer regions of M17”. The wide field image (right image) has been taken with a 130mm refractor but, specifically, M17’s core has been enhanced with a higher resolution image taken with a 431mm reflector (center image).

Messier 17 is one of the brighter regions of a much larger hydrogen cloud that also contains Messier 16. Please click this link to see a wider field, capturing the area with both nebulas. This 1×2 mosaic has been obtained by merging wide field M16 with wide field M17. All images have been taken in narrowband (Ha, OIII and SII) and mapped to natural color, slightly enhancing the OIII emission regions, because these regions are often overwhelmed by Hydrogen red in RGB images and they are more rarely seen in their greenish-bluish splendor. Messier 18, an open cluster, is seen at the very bottom center of the wide field image. The total exposure for M17 has been 16.25 hours and the exposure for M16 has reached 27 hours. The complete mosaic is the result of 43.25 hours of exposure.

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