The WIYN 3.5-m Telescope Overview

The WIYN 3.5-m telescope is a Ritchey-Chrétien telescope with an altitude-azimuth mount. It saw first light (produced its first astronomical image) in 1994.

The telescope houses three mirrors.

1. The primary mirror has a diameter of 3.5 meters or 138 inches, with an edge thickness of 18 inches. Constructed of borosilicate glass at the University of Arizona's Mirror Laboratory, the primary weighs slightly over 2 tons at 4,320 lbs. The mirror is equipped with active mirror supports and thermal controls.
2. The secondary mirror is 1.2 meters across, weighs 263 lbs and was fabricated at Schott Glass and Contraves.
3. The tertiary mirror, measuring 1.2 meters by 0.8 meters flat, weighs 132 lbs. It was fabricated at Schott and Kodak.

The small, lightweight enclosure is well ventilated to follow nighttime ambient temperature. Instruments attached to the telescope allow WIYN to gather data and capture vivid astronomical images routinely of sub-arc second quality. The excellent image quality can be seen in images in the NOAO Image Gallery.

Active optics hardware on the back of the primary mirror, as shown in the above picture, shape the mirror perfectly, insuring the telescope is focused precisely.

The total moving weight of the WIYN telescope and its instruments is 35 tons.

Detailed technical information on the WIYN 3.5m Telescope is available on the WIYN Technical Specifications page.

Instruments Available on WIYN

In 2013 WIYN 3.5-m telescope commissioned an optical imager (the One Degree Imager) that is permanently mounted to one of the Nasmyth ports. The ODI detectors are Orthagonal Transfer Array (OTA) devices, which optimize WIYN's excellent image quality.

The second Nasmyth port allows for a variety of instrumentation.

Hydra is a multi-object spectrometer that utilizes fiber optics placed in the focal plane to simultaneously transmit the light from numerous objects to the Bench Spectrograph. This spectrograph separates starlight according to wavelength to produce a spectrum of each object that is recorded onto a CCD detector.

WIYN also has a near-infrared imager known as WHIRC (WIYN High-Resolution Infrared Camera), which can be used in conjuction with the WIYN Tip-Tilt module (WTTM) to provide high spatial resolution, high sensitivity, and a moderately wide field-of-view.

Several Integral Field Units (IFUs) that feed into the WIYN Bench Spectrograph are also available. Hexpak, Gradpak and Sparsepak.

In 2014 two new Integral Field Units (IFUs) HexPak and GradPak were deployed at WIYN. HexPak was designed with face-on and early type galaxies in mind, with the smaller fibers to be placed on the higher surface brightness galaxy core. GradPak is ideal for edge-on systems, with the smaller fibers placed on or near the midplane.

SparsePak is another Integral Field Unit that feeds into the Bench Spectrograph. Sparsepak is a sparsely packed fiber optics bundle with nearly-integral core that has a special fiber geometry designed to optimize performance for the specific scientific goal of studying the spatial distribution of the internal motions of gas and stars in nearby galaxies, but is also useful in general for the study of galactic and extra-galactic nebulae.