Corona Australis, the constellation of the Southern Crown, are visible here because not because they glow, but because they absorb and reflect. The dust appears bluer when seen near bright stars because it preferentially reflects blue light. The densest knots of dust are so thick that no background stars or interior stars can be seen through them. These knots indicate molecular clouds filled with cool gas where future stars will likely form. The above image spans about 5 degrees while the reflection nebula lies about 500 light-years distant.
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Based on Astronomy Picture Of the Day
Publications with keywords: reflection nebula - molecular cloud
Publications with words: reflection nebula - molecular cloud