Lesson Two : Resolution
Resolution is the degree of clarity and detail that an optical or radio instrument provides. Resolution depends on wavelength and the diameter of the telescope. Because radio waves are so long, we must increase the diameter of the telescopes we use to receive radio waves in order to obtain high-resolution images. In order to achieve the same resolution as an optical telescope, the dish of the radio telescope must be at least 140,000 times larger than the optical instrument!
M100 as seen by the Hubble Space Telescope before and after repairs to improve resolution
NASA / STScI
NASA / STScI
NAIC - Arecibo Observatory, a facility of the NSF
The radio telescope in Arecibo, Puerto Rico is the largest single dish radio telescope in the world. The diameter of the dish is 305 meters, creating a very high resolution radio telescope. However, the resolving power of this dish is still very poor when compared to that of optical instruments.