The Atik 2HS is a monochrome modified web cam cooled by a small fan. The chip size is small but sensitive. It has small pixels which allow reasonable resolution but it is restricted by only being 8bit. The chip is cooled by a small fan. It works particularly well with K3CCDtools software. The camera's small round footprint and it's small pixels means it works very well with the Celestron fastar system. It is a superb introduction to deep sky imaging.