The MMT (Multiple Mirror Telescope) was in operation between 1979 and 1998. The telescope is called 'multiple' because it consisted of 6 mirrors that all worked together with a unified gathering area of a 4.5m telescope, which made it the third largest optical telescope in the world at the time of its dedication. The optical design was created by Aden Meinel.

 

Until the point that the MMT was built, most major optical telescopes used equatorial mounts. The MMT, however, has an altitude-azimouth mount, and all major optical telescopes built since the design of the MMT also display this mount as opposed to the equatorial mount, making it a pioneer in telescope engineering.

 

Since 1998, the MMT has been re-designed so it no longer has multiple mirrors, but one of a diameter of 6.5m. The reason they had originally used 6 mirrors instead of one is because of the difficulty of making a single, large mirror. Roger Angel of the Steward Mirror Laboratory, however, began casting large mirrors using a honeycomb structure, which meant that the mirror did not distort over time. Therefore they changed the structure of the MMT to just house one, larger mirror that would be easier to manipulate resulting in better and sharper images.

 

A downloadable version of the visitor guide for this telescope will be made available soon!