The Keyhole Nebula is a glowing cloud of gas, dust, and stars some 8000 light
years distant toward the constellation Carina.
The Keyhole Nebula contains both bright regions that glow
by means of fluorescence emission from ionized gas, and dark regions that
obscure background light by means of dense molecular gas and dust.
The Keyhole Nebula
is a site of active star formation, and it
contains stars that are ten times as hot and 100 times as massive as the Sun.
The entire Carina Nebula is some 200 lights years across, although the Keyhole
Nebula portion shown here is only about 15 light years across.
The bright star in the middle is Eta Carinae; the red and yellow spikes in up-down direction are due to the CCD, i.e. the 4 Mega-pixel chip used to take the picture, getting saturated so that electrons flow across several pixels.