Spherical astrolabe (15th C.). One point which distinguishes Star Map from the astrolabe is that in both cases, astrolabes were not meant for direct viewing. In other words, one could not do real time work. It would require measurement, enscribing, and a duration of labor, etc. Worth mentioning, the spherical astrolabe did not have a viewing instrument, like the planispheric versions did. This made the planispheric require less work and fewer hours of it in order to chart information.
Astronomers reveal supermassive black hole's intense magnetic field Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a supermassive black hole in a distant galaxy. The results appear in the 17 April 2015 issue of the journal Science.