47 Tucanae is the second brightest "globular cluster" visible from Earth, though it can only
be seen from the Southern Hemisphere. Globular clusters are particularly large, dense collections
of thousands, even millions of stars that are so tightly bound together by gravity that they
stay together for billions of years.
Located about 20,000 light years from Earth, 47 Tucanae remains impressive due to its sheer
size, containing around a million stars. Only a small fraction of the very brightest ones
can be seen in this image. About half of its stars fall within a region 25 light years across
though the entire cluster spans well over 100 light years.
This image is 34 arcminutes across, just over half a degree. The infrared colors of these stars
are very uniform, showing almost no variation.