The 4m Mayall telescope is an optical telescope at the Kitt Peak National Observatory. Construction of the telescope began in 1968 and was finished in 1970, although the mirror was placed later and first light wasn’t seen until 1973. At this time it was the second largest telescope in the world.

 

The telescope was named after the former director of the Kitt Peak National Observatory, Dr. Nicholas Mayall who was director from 1960 to 1971.

 

The mirror was originally planned to be 150 inches in diameter, but it was scaled up to 158 inches (4 metres) as this was the largest that they could make it without having to change the design of the mount. The dome of the telescope weighs around 500 tonnes, and the mirror weighs 15 tonnes, equating to a structure that weighs in excess of 515 tonnes. To support this huge weight, the building underneath has ten hexahedron structures which distributes the pressure over a greater area.

 

Since its completion in 1970, the structure hasn’t received many alterations apart from the addition of 22 vents in the dome. These vents improve circulation of the dome, and also make it easier to cool the instruments and the air around the telescope, to improve seeing conditions.

 

Before the telescope was built, Dr. Mayall was researching the distance scale and the large scale structure of the Universe, which he went on to study with the Mayall telescope. After studying large scale structure, users of the telescope began to concentrate more on galaxies, and especially rotation curves of galaxies.

 

Having determined the rotation curves of galaxies, astronomers were able to study the role of dark matter in the Universe, my finding the mass of dark matter in these galaxies by subtracting the observable mass from the overall mass determined by the rotation curves.

 

An instrument called the Dark Energy Spectroscopic Instrument (DESI) is planned to be placed on the Mayall telescope in 2018, after fears that the scope would be closed down in favour of newer, ‘better’ telescopes. The introduction of the DESI will keep the scope in good use, by creating a 3D map of the universe by observing spectral properties of galaxies, Luminous Red Galaxies LRGs) and quasars.