- Lack of information about 3C 348, the galaxy that produces the radio source Hercules A.
One thing that I know is that the radius of an elliptical galaxy is defined as the "half-light radius", which is the radius within which half of the galaxy's luminosity is contained. Based on an image of radio source Hercules A overlaid with galaxy 3C 348 (which I have provided), and knowing that Hercules A is 1.5 million light years long, I came up with a VERY rough estimate for the galaxy's diameter at about 125,000 lights years (radius of about 62,500 lights years). However, with the limited technology that I have at my disposal, all that I can do is eyeball the image. Are my measurements accurate, or is there a more accurate size to be found for 3C 348?