Caldwell 83, or NGC 4945, is a barred spiral galaxy (like our Milky Way) that appears edge-on. This composite image of the galaxy’s center combines observations taken in visible and infrared light with Hubble’s Wide Field and Planetary Camera 2.

Caldwell 83 is interesting to astronomers because it is the source of the first water megamaser ever found. Masers produce amplified microwave radiation similar to lasers, which amplify visible light. This emission has been observed from a variety of molecular sources throughout the universe, including water molecules. Megamasers, like the water megamaser observed originating from Caldwell 83, are even brighter than regular masers — about 100 million times brighter. The Hubble observations used to construct this image were conducted to help astronomers better understand the environments of water megamasers.

Caldwell 83 was discovered from Australia by the Scottish astronomer James Dunlop in 1826. It is located roughly 12 million light-years from Earth in the constellation Centaurus. The galaxy has an apparent magnitude of 9.3 and can be seen with a small telescope in a dark sky. It will look like a thin, elongated patch of light brightening slightly toward the center, and appears near the small elliptical galaxy NGC 4976. The best time to observe Caldwell 83 is during autumn in the Southern Hemisphere, or during the late spring from southern latitudes in the Northern Hemisphere.

Credit: NASA, ESA, and H. Falcke (Max Planck Institute for Radio Astronomy); Processing: Gladys Kober (NASA/Catholic University of America)