... Here fifteen pictures from the Hubble Space Telescope have been merged to show the great expanse and diverse nature of the nebula. ... Densely packed stars in the core of the globular cluster M15 are shown in this Hubble Space Telescope (HST) image taken in April of 1994. The stars revealed are contained in an area 1.6 light years across and their colors roughly indicate their temperatures - hot stars appear blue, cooler stars look reddish-orange. ... Astronaut F. A Quintet of Galaxies . ...