Proceedings Article | 27 September 2012
Proc. SPIE. 8444, Ground-based and Airborne Telescopes IV
KEYWORDS: Telescopes, Mirrors, Astronomy, Optical fabrication equipment, Lenses, Cameras, Optical fabrication, Space telescopes, Astronomical telescopes, Optical instrument design
The KMTNet telescope Project, sponsored by The Korea Astronomy and Space Science Institute (KASI), is fabricating
three wide-field equatorial mount telescopes of 1.6 meter aperture to conduct continuous observations of the Galactic
bulge region to search for extra-solar planets. Southern latitude sites secured for these telescopes are SAAO (South
Africa), CTIO (Chile), and SSO (Australia). A prime-focus configuration, along with a four-lens corrector achieves the
2.8 degree diagonal FOV. The basic mechanical design utilizes a scaled-up version of the successful 2MASS Telescopes
built by the authors in the late 1990's. Scaling up of components has presented challenges requiring several iterations of
the detailed mechanical analysis as well as the optical analysis due to interaction with mounting assemblies for the
optical components. A flexure-style focus mechanism, driven by three precision actuators, moves the entire headring
assembly and provides real-time focus capability, and active primary mirror cooling is implemented for the Zerodur
primary. KMTNet engineering specifications are met with the current design, which uses Comsoft's Legacy PCTCS for
control. A complete operational telescope and enclosure are scheduled for installation in Tucson, AZ prior to shipping
the first hardware to CTIO in order to verify tracking, optical characteristics at various attitudes, and overall observatory
functionality. The cameras, being fabricated by The Ohio State University Department of Astronomy, Imaging Sciences
Laboratory (ISL), are proceeding in parallel with the telescope fabrication, and that interface is now fixed. Specifics of
the mechanical and optical design are presented, along with the current fabrication progress and testing protocols.
