
The Triangulum Galaxy (M33) is a face-on spiral and the third-largest member of our Local Group, after the Milky Way and Andromeda. It is famous as the subject of the largest, sharpest Hubble portrait of a spiral galaxy ever assembled — a 665-million-pixel mosaic resolving roughly 25 million individual stars — and is among the most distant objects visible to the naked eye under dark skies.