M33 and the Trangulum in a Circle!
Optics: RC Optical System 20" F/8.2 (4165.6 mm Focal Length) Date: Aug-Sept 2020
Camera: SBIG STXL-11000 with AO-X Adaptive Optics Location: Columbus, Texas
Exposure: LRGB = 420:90:90:120 minutes Imager: Kent E. Biggs
A Triangulum in a Circle! M33 is so large visually that it overflows the CCD camera in this image. For comparison, the “Circle” is a reference to the moon which can be seen by "hovering" over the image using a pointer or mouse. The moon image is true in scale compared to the galaxy’s own size! M33 is called the Triangulum Galaxy, not because it resembles a triangle, but because it is a large, bright, galaxy located in the direction of the constellation Triangulum, Latin for the Triangle. M33 is easily visible in binoculars and small telescopes and is the third-largest member of the Local Group of galaxies, smaller only than our own Milky Way Galaxy and the Andromeda Galaxy. It actually extends beyond this image to over twice the size of the full moon! M33 is about 60% the size of the Milky way at about 60,000 light years across and contains only about 10 percent of the 400 billion stars present in our own galaxy. It is a Class SAs galaxy meaning it is spiral in nature hence the "S" in SAs, not elliptical “E”. It lacks a Bar structure, so it is "A" in SAs not “B”, and the small “s” in SAs designates the spiral arms emerge from the small nucleus of this galaxy rather than from a ring “r”. Unlike many other galaxies, M33's nucleus is quite small and likely does not contain a supermassive black hole based on the observed motion of stars in the central area. Two spiral arms of this galaxy are very visible in this image clear to the edge. One of the most incredible aspects of M33 is that, astronomically speaking, it is so close to us at only 2.7 million light years away, therefore, many objects including star clusters as well as dark, emission, and planetary nebula are clearly visible even with medium size telescopes. They are being studied by the largest telescopes on earth as M33 is a treasure trove of different objects that will be explored for centuries to come. The stats for M33 are RA 01h 33m 51s, Dec +30° 39' 37", Mag: 6.3, Size 65.6'x38.0', Class SA(s)cd.