Astronomy Picture of the Day

Explanation: What's that bright red spot between the Lagoon and Trifid Nebulae? Mars. This gorgeous colour deep-sky photograph captured the red planet passing between the two notable nebulae -- catalogued by the 18th century cosmic registrar Charles Messier as M8 and M20. M20 (upper right of centre), the Trifid Nebula, presents a striking contrast in red/blue colours and dark dust lanes. Across the bottom right is the expansive, alluring red glow of M8, the Lagoon Nebula. Both nebulae are a few thousand light-years distant. By comparison, temporarily situated between them both, is the dominant "local" celestial beacon Mars. Taken last week, the red planet was only about 10 light-minutes away.