IC 348 is a young (about 2 million years old) open star cluster located at a distance of about 300 pc in the Perseus molecular cloud complex.
Below is a very deep J band (1.2 micrometer) image I have obtained at the 3.5 m telescope on Calar Alto. In this image, objects as faint as magnitude J = 21 are clearly visible. This is deep enough to reveal not only the faintest stars of the cluster, but also the sub-stellar objects (i.e. young brown dwarfs) with masses of down to 0.005 solar masses. This data set has been used to study the brown dwarf population of IC 348 (see paper # 35 in the publication list).