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M17 Region in Sagittarius



Scope: Explore Scientific MN152 Maksutov Newtonian at f/4.8, Location:  Laguna Mountains, CA   15 July 2015  Camera: ST 8300M

Exposure: Exposure: 10 x 5 min  (1x1 bin) exposure with UV/IR block,  16 x 8 min (1x1 bin) H-Alpha exposures, 8 x 4 min (2x2 bin) RGB exposures.

Processing: Data Collection -  Sequence Generator Pro (as FITs).  Calibrated, stacked (Kappa Sigma Combine) Deep Sky Stacker, LRGB channel registration, equalization, and central gradient removal - Astroart.  Curves, Levels, RGB combine Images Plus. Luminance layering and finishing  - Photoshop. This image is a  HaLRGB combine with Luminance layering. The H-Alpha exposure stack was screen blended to the Luminance exposures  to form the Luminance layer.   Color saturation in LAB color;    Final Image size is approximately 2800x2100.

North is up in this image. Central in this image is the emission / reflection nebula M17. It is also known as  Sharpless 45, Gum 81a. Embedded in the nebula is the young star cluster NGC 6618. This is a very energetic region of a larger molecular cloud known as  (M17SW). The NGC 6618 cluster contains over 800 stars; 100 of them are hotter than B9. This is compared to the Orion Nebula which has 8 such stars; NGC6618 also has 25 time the UV flux than that of the Orion nebula so this region is a very energetic space.  Just to the right is a brighter area cataloged as Gum 81b. These two bright areas are part of the same structure and they are bisected by a dark lane running between them. There is the overriding large dark nebula known as LDN 359 of which only about  a quarter of it lies in this image. These objects and some of the brighter stars are identified in  the annotated image.  M17's distance from Earth is estimated to be between 4,300 to 6,000 light years lying in the Sagittarius or Sagittarius-Carina arm of the Milky Way. This image replaces an earlier image that can be seen in the Archives here.  Horizontal FOV is 88'

Image center is approximately - Equatorial 2000: RA: 18h 20m 54.6s Dec: -1607'23"


All images and content remain the property of Jim Thommes - copyright 2003 - 2015 copyright 2003 - 2012

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