The 'Sab' Type Galaxy Messier 81 (IMAGE) Royal Astronomical Society Caption The 'Sab' type galaxy Messier 81, located in the northern constellation of Ursa Major, has a black hole mass of 68 million Suns. Credit Credit: Spitzer Space Telescope / Benjamin Davis. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.