Caldwell 78

This beautiful globular cluster is best seen from equatorial latitudes.

Distance

22,000 light-years

Apparent Magnitude

6.3

constellation

Corona Australis

object type

Globular Cluster

Caldwell 78
This image of globular star cluster Caldwell 78, also known as NGC 6541, is a composite of observations taken in visible and ultraviolet light by Hubble’s Wide Field Camera 3. These observations were made to better characterize the cluster’s stellar populations.
NASA, ESA, and G. Piotto (Università degli Studi di Padova); Processing: Gladys Kober (NASA/Catholic University of America)

The globular star cluster Caldwell 78, also known as NGC 6541, was first observed in the year 1826. The Italian astronomer Niccolò Cacciatore and the Scottish astronomer James Dunlop discovered the cluster independently within just a few months of each other.

C78 is best observed from equatorial latitudes in the Northern Hemisphere during the summer and from the Southern Hemisphere during the winter. The cluster has an apparent magnitude of 6.3 and is located in the constellation Corona Australis, roughly 22,000 light-years from Earth. The cluster can be spotted with binoculars, but will dazzle in a small telescope. A larger telescope will resolve some of the cluster’s individual stars.

Traditionally, astronomers believed that globular clusters were made up of stars that have both similar ages and similar chemical abundances. However, recent studies suggest that this simplistic view is not always true. It seems as though many globular clusters contain stars with different chemical abundances relative to one another (or “multiple populations”), suggesting the stars formed at different times.

This image of C78 is a composite of observations taken in visible and ultraviolet light by Hubble’s Wide Field Camera 3. These observations were made to better characterize the cluster’s stellar populations.

Star chart for Caldwell 78 showing the outlines of constellations and the location of C78.
This star chart for Caldwell 78 represents the view from mid-southern latitudes for the given month and time.
Image courtesy of Stellarium

Glossary

Apparent Magnitude - The brightness of an astronomical object as seen from Earth, influenced by the object's distance from Earth, its absolute magnitude, and even gas and dust that lie between the object and Earth.

Globular Cluster - A spherical group of stars that are gravitationally bound to each other, with most of the stars concentrated at the cluster’s center.

Explore Hubble's Caldwell Catalog

The following pages contain some of Hubble’s best images of Caldwell objects.

Stars with four diffraction spikes dot the scene against a black backdrop.

Caldwell 1

Also known as NGC 188, this group of stars formed from a large cloud of gas making the stars roughly…

Red cloud of dust with a bright white star in the center of it. Lots of reddish and orangish stars in the background.

Caldwell 2

This shell of gas is expanding outward, away from the dying star within.

Large grouping of bright white, blue and red stars. Lightly colored blue dust surrounds the stars.

Caldwell 3

This barred spiral galaxy was first spotted by British astronomer William Herschel in April 1793 in the constellation Draco.