Astronomy Picture of the Day

Explanation: On the right, dressed in blue, is thePleiades. Also known as theSeven Sisters andM45,the Pleiadesis one of the brightest andmost easily visibleopen clusterson the sky.The Pleiadescontains over 3,000 stars, is about 400 light years away, and only 13 light years across.Surrounding the stars is a spectacular bluereflection nebula made of finedust. Acommon legend is that one of the brighter starsfaded since the cluster was named.On the left, shining in red, is theCalifornia Nebula. Named for its shape, theCaliforniaNebula is much dimmer and hence harder to seethan the Pleiades. Also known as NGC 1499, this mass of red glowinghydrogen gas is about 1,500 light years away.Although about 25 full moons could fitbetween them, the featured wide angle, deep field image composite has capturedthem both. A careful inspection of the deep image will also reveal the star forming region IC 348 and the molecular cloud LBN 777 (the Baby Eagle Nebula).