Take a Schmidt Newtonian, replace the Schmidt corrector with a salad bowl Maksu-tov corrector plate, and the result is a Maksutov Newtonian. It is not quite that simple, but that is the basic idea. Back in the mid-1990s these MNTs were the darlings of the amateur astronomy chattering classes, the on-and offline astronomy pundits and writers. That was understandable. If any reflecting telescope approaches premium apochromatic refractors in image quality while beating them at the aperture/ price game, it is the MNT. Why, then, has the popularity of MNTs waned?
Maybe this is because they are such specialized instruments. These are remarkable telescopes for looking, for visual use, especially for targets that benefit from high resolution such as the Moon and planets. On these subjects, MNTs may equal the best refractors. That comes at a price, however. One of the reasons MNTs are able to offer excellent images is by using very small secondary mirrors. The typical obstruction in these scopes is below 30%, and often below 25%. Although Maksutov Newtonians, which are available in relatively fast focal ratios like f/6 to f/7, are capable of producing great deep sky views, their tiny secondaries pretty much rule out any serious deep sky imaging. As this book goes to press, several new MNTs, including one by Orion (U.S.) have become available that are more suited for imaging. Unfortunately, their larger secondary mirrors reduce the MNT's legendary contrast advantage.
Was this article helpful?