A Dragone telescope or Dragone-design telescope is an off-axis reflector telescope making use of a secondary mirror with a particular curve. Corrado Dragone described the design for antennas in his 1978 paper "Offset multireflector antennas with perfect pattern symmetry and polarization discrimination" (Bell System Technical Journal, vol. 57, Sept. 1978, p. 2663-2684) and subsequent 1980s papers. The general geometry is applicable to optical as well as radio telescopes. It has the advantage of preserving the polarization of the incoming electromagnetic radiation, which has made it of particular interest for telescopes aimed at the cosmic microwave background.
Two subtypes are called open-Dragone design and crossed-Dragone design, the latter having the light path cross itself to reach the focal plane.
The term Mizuguchi-Dragone design gives co-credit to the 1978 paper by Yoshihiko Mizuguchi et al.: "Offset Gregorian Antenna" (Electronics and Communications in Japan, vol. 61, Mar. 1978, p. 58-66). My guess is the papers describe essentially the same design.
Astronomers are currently refining and making use of the designs and considering them for current and future projects. The following use them: