This image is split into multiple parts. Across the top is an image of a portion of the Andromeda Galaxy, with the core partly visible to the left and continuing off the image. A portion of the galaxy's spiral arms are to the right. The location of the star clusters is highlighted with a callout box on the arms. On the bottom left, the locations of star clusters are marked in the callout box. On the bottom right, the clusters themselves are imaged and the stars visible in bright blue and red.

Young, blue star clusters in M31

This Hubble mosaic of 414 photographs of the M31, or the Andromeda galaxy. On the bottom left is an enlargement of the boxed field (top) reveals myriad stars and numerous open star clusters as bright blue knots,spanning 4,400 light-years across. On the bottom right are six bright blue clusters extracted from the field. Each cluster square is 150 light-years across.

Credits: NASA/ESA, J. Dalcanton, B.F. Williams, L.C. Johnson (Univ. of Washington), PHAT team, and R. Gendler