ABSTRACT. The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT in the spring of 2004. In the configuration pioneered by the Autofib instrument at the Anglo-Australian Telescope, Hectospec's fiber probes are arranged in a radial "fisherman on the pond" geometry and held in position with small magnets. A pair of high-speed, six-axis robots move the 300 fiber buttons between observing configurations within ∼300 s, and to an accuracy of ∼25 mm. The optical fibers run for 26 m between the MMT's focal surface and the bench spectrograph, operating at . Hectochelle, another high-dispersion bench spectrograph R ∼ 1000-2000 offering , is also available. The system throughput, including all losses in the telescope optics, fibers, R ∼ 35,000 and spectrograph, peaks at ∼10% at the grating blaze in 1Љ FWHM seeing. Correcting for aperture losses at the 1Љ .5 diameter fiber entrance aperture, the system throughput peaks at ∼17%, close to our prediction of 20%. Hectospec has proven to be a workhorse instrument at the MMT. Together, Hectospec and Hectochelle have been scheduled for of the available nights since its commissioning. Hectospec has returned approximately 60,000 1 3 reduced spectra for 16 scientific programs during its first year of operation.

Binospec is a high throughput, 370 to 1000 nm, imaging spectrograph that addresses two adjacent 8ʹ by 15ʹ fields of view. Binospec was commissioned in late 2017 at the f/5 focus of the 6.5m MMT and is now available to all MMT observers. Aperture masks cut from stainless steel with a laser cutter are used to define the entrance apertures that range from 15ʹ long slits to hundreds of 2ʺ slitlets. System throughputs, including the MMT's mirrors and the f/5 wide-field corrector peak at ~30%. Three reflection gratings, duplicated for the two beams, provide resolutions (λ/Δλ) between 1300 and >5000 with a 1ʺ wide slit. Two through-the-mask guiders are used for target acquisition, mask alignment, guiding, and precision offsets. A full-time Shack-Hartmann wave front sensor allows continuous adjustment of primary mirror support forces, telescope collimation and focus. Active flexure control maintains spectrograph alignment and focus under varying gravity and thermal conditions.

The Hectochelle is an optical band, fiber-fed, multiobject echelle spectrograph deployed at the MMT Observatory on Mount Hopkins, Arizona. The optical fibers that feed the Hectochelle are positioned by the Hectospec robot positioner on the MMT f/5 focal surface, and the Hectochelle shares an optical fiber feed system with the Hectospec, a moderate-dispersion spectrograph that is collocated with the Hectochelle. Hectochelle can record up to 240 spectra simultaneously at a resolution of 38,000. Spectra cover a single diffractive order that is approximately 150 Å wide. The total potential operating passband of the Hectochelle extends from 3800 Å to 9000 Å. Operated in conjunction with the MMT f/5 secondary, the MMT wide-field corrector, and the atmospheric dispersion compensator, the patrol field is 1°in diameter and the individual fiber slits are 1.5′′ in diameter. The throughput of the combined telescope, fiber feed, and spectrograph is measured to be 6.1% at 5275 Å, exclusive of atmospheric extinction. A 20 minute observation of a V ¼ 15 F-type star yields a signal-to-noise ratio of 35 per resolution element. Hectochelle had first light 2003 December 4 and continues to be operated at the MMT today.

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