The Mayall Telescope has a 4-meter, or 158 inch, primary mirror.

The blue "horseshoe" equatorial mounting supports and moves the telescope. Older photographs show the telescope with a yellow yoke. The mount rotates east to west to track the earth's rotation at a compensated speed. Weighing 300 tons, the mounting turns upon 8 hydrostatic bearings with a film of oil only 0.004 inches thick.

The 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile is a twin of the Mayall.

The Fourier Transform Spectrograph was an early, yet innovative, infrared spectrograph used at the Mayall 4-meter telescope.

Infrared radiation has a longer wavelength than visible light and cannot be perceived by humans, yet from the FTS control room researchers separate this type of light into a spectrum for investigation.

The Mayall Telescope is a reflector, not refractor, telescope. That means a series of curved mirrors rather than lenses focus light into an image.

The 4-meter mirror is a solid piece of quart glass ground into a parabolic, or concave, shape. The secondary mirror's shape is convex or hyperbolic, opposite that of the primary.

In a Cassegrain telescope, the secondary mirror reflects light through a hole in the center of the main, objective mirror where the image is formed. Here, attached to the bottom of the telescope will be a light detector, an electronic camera, or a spectrograph.

This arrangement of mirrors is named for its inventor, 18th century French optician Guillame Cassegrain.

Factors that will determine an astronomer's salary include formal education and work experience.

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