NGC 6559 is a

star-forming region Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

located at a distance of about 5000 light-years from Earth, in the constellation of Sagittarius, showing both emission (red) and reflection (bluish) regions.

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* * - one of the three nebulae shown was NGC 6559 *
NGC 6559
Emission nebulae Reflection nebulae 6559 Star-forming regions Sagittarius (constellation) {{nebula-stub