Astronomy Picture of the Day

Explanation: South is toward the top in this colourful close-up view of the Great Carina Nebula (NGC 3372), famous star-forming region of the southern sky. Covering an area surrounding the dusty Keyhole Nebula (NGC 3324) near picture centre, the image spans about 40 light-years within the larger Carina Nebula at an estimated distance of 7,500 light-years. Like the more northerly Orion Nebula, the bright Carina Nebula is easily visible to the naked-eye. But the dramatic colours in this telescopic picture are mapped colours, based on three exposures through narrow filters each intended to record the light emitted by specific atoms in the gaseous nebula. Sulfur is shown in blue, hydrogen in green and oxygen in red hues. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun. Highlighted by diffraction spikes, Eta is just above and right (east) of the Keyhole.