We present the design, assembly, alignment, and verification process of the wide field corrector for the Korea Microlensing Telescope Network (KMTNet) 1.6 meter optical telescope. The optical configuration of the KMTNet telescope is prime focus, having a wide field corrector and the CCD camera on the topside of Optical Tube Assembly (OTA). The corrector is made of four lenses designed to have all spherical surfaces, being the largest one of 552 mm physical diameter. Combining with a purely parabolic primary mirror, this optical design makes easier to fabricate, to align, and to test the wide field optics. The centering process of the optics in the lens cell was performed on a precision rotary table using an indicator. After the centering, we mounted three large and heavy lenses on each cell by injecting the continuous Room Temperature Vulcanizing (RTV) silicon rubber bonding via a syringe.
The Korea Astronomy and Space Science Institute (KASI) are under development three 1.6m optical telescopes for the
Korea Micro-lensing Telescope Network (KMTNet) project. These will be installed at three southern observatories in
Chile, South Africa, and Australia by middle 2014 to monitor dense star fields like the Galactic bulge and Large
Magellanic Cloud. The primary scientific goal of the project is to discover numerous extra-solar planets using the
gravitational micro-lensing technique. We have completed the final design of the telescope. The most critical design
issue was wide-field optics. The project science requires the Delivered Image Quality (DIQ) of less than 1.0 arcsec
FWHM within 1.2 degree radius FOV, under atmospheric seeing of 0.75 arcsec. We chose the prime-focus configuration
and realized the DIQ requirement by using a purely parabolic primary mirror and four corrector lenses with all spherical
surfaces. We present design results of the wide-field optics, the primary mirror coating and support, and the focus system
with three linear actuators on the head ring.
In this paper, we provide an overview of the adaptive optics (AO) program for the Thirty Meter Telescope (TMT) project, including an update on requirements; the philosophical approach to developing an overall AO system architecture; the recently completed conceptual designs for facility and instrument AO systems; anticipated first light capabilities and upgrade options; and the hardware, software, and controls interfaces with the remainder of the observatory. Supporting work in AO component development, lab and field tests, and simulation and analysis is also discussed. Further detail on all of these subjects may be found in additional papers in this conference.
The adaptive optics system for the Gemini South telescope, currently in the design phase, consists of several major subsystem. The largest subsystem, called the AO module, contains most of the optics and electronics and is mounted on one of the Cassegrain instrument ports. The initial system will be a conventional laser guide star AO system, but the plan is to eventually expand it to a multi-conjugate system. The system is being designed to readily add the components necessary to upgrade to a multi-conjugate system. This paper describes the design challenges encountered and solutions that were derived for the AO module design. The complexity of the multi-conjugate version is illustrated, including optical, mechanical, electronic and controls issues.
The multi-conjugate adaptive optics (MCAO) system design for the Gemini-South 8-meter telescope will provide near-diffraction-limited, highly uniform atmospheric turbulence compensation at near-infrared wavelengths over a 2 arc minute diameter field-of-view. The design includes three deformable mirrors optically conjugate to ranges of 0, 4.5, and 9.0 kilometers with 349, 468, and 208 actuators, five 10-Watt-class sodium laser guide stars (LGSs) projected from a laser launch telescope located behind the Gemini secondary mirror, five Shack-Hartmann LGS wavefront sensors of order 16 by 16, and three tip/tilt natural guide star (NGS) wavefront sensors to measure tip/tilt and tilt anisoplanatism wavefront errors. The WFS sampling rate is 800 Hz. This paper provides a brief overview of sample science applications and performance estimates for the Gemini South MCAO system, together with a summary of the performance requirements and/or design status of the principal subsystems. These include the adaptive optics module (AOM), the laser system (LS), the beam transfer optics (BTO) and laser launch telescope (LLT), the real time control (RTC) system, and the aircraft safety system (SALSA).
We describe the adaptive optical (AO) requirements, optical design, and expected performance of a near-infrared AO coronagraph for a 30 meter class giant telescope. The optical design of the instrument consists of back-to-back finite conjugate relays, each containing a collimated space between a pair of toric mirrors. The first collimated space contains the atmospheric dispersion compensator and the AO components, which are a tip/tilt mirror, a MEMS deformable mirror, and a beamsplitter for the wavefront sensing path. An occulting disk or similar focal plane mask is located at the intermediate image between the two relays, and a Lyot stop is placed at the pupil plane in the second relay. The required AO order of correction for a Strehl ratio of 0.9 at a wavelength of 2.2 microns is about 150 by 150, and the required control bandwidth is 42 Hz. The limiting magnitude at this level of performance is estimated to be 10.4.
In the near future, the Gemini Observatory will offer Laser Guide Star Adaptive Optics (LGS AO) observations on both Gemini North and South telescopes. The Gemini North AO system will use a 10W-class sodium laser to produce one laser guide star at Mauna Kea, Hawaii, whereas the Gemini South AO System will use up to five such lasers or a single 50W-class laser to produce one to five sodium beacons at Cerro Pachon, Chile. In this paper we discuss the similarities and differences between the Gemini North and South Laser Guide Star Systems. We give a brief overview of the Gemini facility Adaptive Optics systems and the on-going laser research and development program to procure efficient, affordable and reliable lasers. The main part of the paper presents the top-level requirements and preliminary designs for four of the Gemini North and South Laser Guide Star subsystems: the Laser Systems (LS), Beam Transfer Optics (BTO), Laser Launch Telescopes (LLT), and their associated Periscopes.
This theoretical discussion deals with obliquely projected images on the surface of curved viewing screens. Resulting perspective and geometrical distortions are usually precorrected with computer software in nearly real time, or by optical printing methods in the case of film. Owing to the significant technical and cost overhead of these methods, there is an interest in producing real-time passive correction using optics supplemental to the normal projection lens. Several concepts to this end are described.