A low activity, star-formation region in the constellation Perseus, as seen by Planck. This long-wavelength image covers a square region of 13 by 13 degrees (which is equivalent 26 by 26 full moons). It is a three-color combination constructed from three of Planck's nine frequency channels: 30, 353 and 857 gigahertz.

Planck is measuring the sky at nine wavelengths of light, three of which are shown here.