Object: NGC 6357
NGC 6357 is a very large, faint emission nebula located in the “stinger” area of the constellation Scorpius. Because it never gets very high above the horizon in the continental US it’s a fairly tough object for US astro-imagers. One of my favorite H-alpha targets, NGC 6357 was discovered by John Herschel in 1837 from the Cape of Good Hope, Africa. Lying approximately in the plane of the Milky Way galaxy some 5500 light years from Earth, light from this object is significantly extincted in the blue wavelengths because of the vast amount of intervening galactic dust between us and it. Its stellar nursery of bright blue O-type stars is therefore substantially muted in all but the red wavelengths, with the overall nebula taking on a deep ruddy hue in color images.
- Team: Dave Jurasevich and Howard Hedlund
- Filters: Tru-Balance 5 nm H Alpha Filter
- Exposure: Ha 3 x 6 x 1200 sec, 1x1 bin
- Date: June and July 2014
- Software: CCDStack 2, Photoshop CS5