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The Keck Cosmic Web Imager (KCWI) is a new facility instrument being developed for the W. M. Keck Observatory and funded for construction by the Telescope System Instrumentation Program (TSIP) of the National Science Foundation (NSF). KCWI is a bench-mounted spectrograph for the Keck II right Nasmyth focal station, providing integral field spectroscopy over a seeing-limited field up to 20" x 33" in extent. Selectable Volume Phase Holographic (VPH) gratings provide high efficiency and spectral resolution in the range of 1000 to 20000. The dual-beam design of KCWI passed a Preliminary Design Review in summer 2011. The detailed design of the KCWI blue channel (350 to 700 nm) is now nearly complete, with the red channel (530 to 1050 nm) planned for a phased implementation contingent upon additional funding. KCWI builds on the experience of the Caltech team in implementing the Cosmic Web Imager (CWI), in operation since 2009 at Palomar Observatory. KCWI adds considerable flexibility to the CWI design, and will take full advantage of the excellent seeing and dark sky above Mauna Kea with a selectable nod-and-shuffle observing mode. In this paper, models of the expected KCWI sensitivity and background subtraction capability are presented, along with a detailed description of the instrument design. The KCWI team is lead by Caltech (project management, design and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (program oversight and observatory interfaces). The optical design of the blue camera for the Keck Cosmic Web Imager (KCWI) by Harland Epps of the University of California, Santa Cruz is a lens assembly consisting of eight spherical optical elements. Half the elements are calcium fluoride and all elements are air spaced. The design of the camera barrel is unique in that all the optics are secured in their respective cells with an RTV annulus without additional hardware such as retaining rings. The optical design and the robust lens mounting concept has allowed UCO/Lick to design a straightforward lens camera assembly. However, alignment sensitivity is a strict 15 μm for most elements. This drives the fabrication, assembly, and performance of the camera barrel.

The Automated Planet Finder (APF) is a new telescope on Mount Hamilton with an instrument designed and built by UCO. During the development of the instrument's camera lens assembly the largest optical element fractured during fabrication. The glass grade is a relatively robust material and not known for any special sensitivity. Transient thermal and structural FEA modeling was performed on the element geometry for several glass materials to better understand the mechanics involved and the relative nature of the properties and response of the glass that failed. Results show that the glass in question yielded the highest surface stresses of all those considered and high internal stresses as well. The analysis technique described here is a simple tool that can be used to evaluate a material and make valid comparisons with others.

We present an update on efforts at University of California Observatories to develop improved optical coatings for astronomical telescopes and instruments. The main thrust has been in the areas of protected silver mirror coatings and sol-gel based anti-reflection coatings. We report on the performance of silver coatings used for several years in Keck and Lick instruments, as well as that on the Lick 1-m telescope. We discuss process improvements, including use of reactive ion-assisted deposition of oxides. Sol-gel based AR coatings have been exposed to cryogenic environments to test their suitability for IR instruments, with encouraging results. Finally, we describe our plans for future work.

A mosaic of two 2k x 4k fully depleted, high resistivity CCD detectors was installed in the red channel of the Low Resolution Imaging Spectrograph for the Keck-I Telescope in June, 2009 replacing a monolithic Tektronix/SITe 2k x 2k CCD. These CCDs were fabricated at Lawrence Berkeley National Laboratory (LBNL) and packaged and characterized by UCO/Lick Observatory. Major goals of the detector upgrade were increased throughput and reduced interference fringing at wavelengths beyond 800 nm, as well as improvements in the maintainability and serviceability of the instrument. We report on the main features of the design, the results of optimizing detector performance during integration and testing, as well as the throughput, sensitivity and performance of the instrument as characterized during commissioning.

Aspherical surfaces on lenses are difficult to produce and test. There are many innovative approaches used today to address the complexities of this process. The size, quality, and quantity of the lens to be produced dictate the best approach. The UCO/Lick Observatory Optical Lab has fabricated aspheric lenses to diameters over 12 inches using fabrication and testing techniques developed specifically for high quality, one-of-a-kind lenses, with axi-symmetric profiles and significant departures from sphere. This paper describes the manufacturing procedures used at UCO/Lick to fabricate aspheric lenses typical for today's astronomical applications.

Lenses made from the optical crystal, calcium fluoride, are required in spectrograph camera designs for many of today's astronomical telescopes. Often these cameras are of large aperture with lens diameters in the 12 inch to 15 inch range. This material is highly susceptible to mechanical and thermal shock, resulting in fracturing. Large calcium fluoride lenses, with their varying thickness profiles, require techniques and precautions in processing from raw material to a finished lens that aren't required with windows or small lenses. This paper describes techniques learned and used at the Lick Observatory Optical Lab that deal with working this delicate crystal and producing large finished lenses.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The DEIMOS Spectrograph Camera contains tow doublets and a triplet. Each group contains materials differing in thermal coefficient expansion, mechanical and optical properties. To mate the elements and at the same time accommodate large camera temperature changes, we will fill the space between with an optical fluid couplant. We selected candidate couplants, lens-support materials, and fluid-constraining materials based on published optical, mechanical and chemical properties. We then tested the chemical reactivity between the coupling fluids, lens-support and fluid- constraining materials. We describe here the test configurations, our criteria for reactivity, and the result for various test durations. We describe our conclusions and final choices for couplant and materials.

DEIMOS is a large multi-object spectrography with an imaging mode that is being built for the W. M. Keck 2 Telescope. The camera contains nine lens elements in five groups. The overall length of the camera and detector assembly is 0.67 meters, and the largest element is 0.33 meters in diameter. Typical centration and spacing tolerances are at the level of 25 microns. We describe the error budget, the design of the lens-supporting structure, and the assembly procedures.

The Echellette Spectrograph and Imager (ESI), currently being delivered for use at the Cassegrain focus of the Keck II telescope employs an all-spherical, 308 mm focal length f/1.07 Epps camera. The camera consists of 10 lens elements in 5 groups: an oil-coupled doublet; a singlet, an oil- coupled triplet; a grease-coupled triplet; and a field flattener, which also serves as the vacuum-dewar window. A sensitivity analysis suggested that mechanical manufacturing tolerances of order +/- 25 microns were appropriate. In this paper we discuss the sensitivity analysis, the assembly and the testing of this camera.

Fabrication of the secondary mirrors for the W. M. Keck Telescopes required advances in techniques and tools for grinding, polishing, and testing. We describe the development and performance of those techniques and tools.

The Diode Array Pumped Kilowatt Laser (DAPKL) has demonstrated more than an order of magnitude increase in brightness and average power for short pulse diode-pumped solid-state lasers since its inception in 1991. Significant advances in component technology has been demonstrated, including development of a diffusion bonding process for producing large slabs of Nd:YAG laser material. Phase conjugation by stimulated Brillouin scattering has been demonstrated with high reflectivity and fidelity in a simple focused geometry with input powers of 100 W. Pulse energies at 1.06 μm of up to 10 J per pulse have been demonstrated with a beam quality of 1.25 times diffraction limited at 33 Hz. An average power of 940 Watts at 100 Hz has been obtained with two times diffraction limited beam quality. Efficient frequency doubling with an average power of 165 W has been demonstrated with 5 J per pulse at 0.53 μm. The system has been packaged in a compact brassboard for long term stability and reliability of operation.

This paper describes the design of DEIMOS -- a dual beam, off axis, multi object spectrograph of medium resolution, being designed for the Keck II telescope on Mauna Kea in Hawaii. The difficult and advanced scientific goals of the DEIMOS project have generated many challenging design requirements. The DEIMOS team at Lick Observatory has been responding to these challenges with new and unique concepts in instrument design and fabrication.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.