Astronomy Picture of the Day

Explanation: Will the spider ever catch the fly? Not if both are large emission nebulae toward the constellation of the Charioteer (Auriga). The spider-shaped gas cloud in the image centre is actually an emission nebula labelled IC 417, while the smaller fly-shaped cloud on the left is dubbed NGC 1931 and is both an emission nebula and a reflection nebula. About 10,000 light-years distant, both nebulae harbour young star clusters. For scale, the more compact NGC 1931 (Fly) is about 10 light-years across. The featured deep image, captured over 20 hours during late January in Berkshire UK, also shows more diffuse and red-glowing interstellar gas and dust.