NGC 6559 is part of a larger star-forming region in the southern constellation Sagittarius. The dark structure that resembles a Chinese dragon is caused by cool dust that absorbs background radiation from hydrogen gas that glows in red light due to ionization from nearby stars. This region lies less than one degree away from the popular Lagoon Nebula (M8), and is located some 5,000 light-years away toward the center of our Milky Way galaxy. At this distance the length of the cloud (diagonally across the image) is about 7 light-years.
The intricate details and wispy structure in the dark cloud is determined by turbulence flow dynamics influenced by variables such as nearby star radiation and motions of other nearby gas and dust. These kinds of clouds illustrate how past generations of stars are dispersing heavier elements into our galaxy, material that will seed future generations of stars and possibly planetary systems.
This image of NGC 6559 was obtained on the night of July 10, 2005 (UT) at the Gemini South Telescope in Chile. The image was a combination of four images obtained with the following filters and total exposure times per filter:
g’ 480 seconds
r’ 480 seconds
i’ 480 seconds
H-alpha 1200 seconds
The stability of the atmosphere was very good for the duration of the data acquisition and allowed high image quality at the following levels:
Filter Image Quality (FWHM)
The images were combined in chromatic order by assigning the following colors to each filter:
Image Orientation: East = down, North = right (rotated 165 degrees east of north)