About image M 33, also known as the Triangle galaxy, is a spiral galaxy of type SA (s) cd about 3 million light years from Earth and located in the constellation of the Triangle. It is the second non-dwarf galaxy closest to the Milky Way after the Andromeda Galaxy (M31). It can be seen with binoculars under dark skies, through which it looks like an oval spot with irregular contours; under a dark sky and without light pollution it is even possible to notice it with the naked eye, through the distracted vision. M33 is part of the Local Group together with the Milky Way and the Andromeda galaxy. Note on the lower left, on the edge of the galaxy, a reddish speckle: it is NGC 604, an HII region (ie an ionized hydrogen emission nebula) very bright with a diameter of almost 1500 light years.
Technical data Optic Apo refractor Tecnosky 115/800 f/6.9 Mount Losmandy G11 with FS2 Camera Canon 400D Baader modified Filters - Guiding system Apo refractor Skywatcher 80ED Exposure details 30x480" iSO 800 Total integration 2.7h Acquisition Maxim, PHD2 Processing Maxim, Iris, Photoshop CS5 SQM-L 21.4 Location Pian dell'Armà (Pavia, Italy) Date 15 September 2012