GeminiFocus October 2018 | Page 21

components are integrated and undergoing testing in Chicago at this time; the pre-ship acceptance test is scheduled for late Octo- ber. The plan is to commission the Front End on the telescope first, using a simple detec- tor, so that we are ready to commission the MAROON-X spectrograph when it arrives next year. TOPTICA Laser Update As a proven, stable laser platform, the new TOPTICA fiber laser is expected to bring more power and stability to Gemini North (GN) laser operations. We continue to make progress with the installation of the system. With the old Lockheed Martin Coherent Technologies laser removed and telescope restored, we were able to begin modifying the telescope to accept the new laser and, in June, we began preparations to install it. ing logistically and required careful planning. The addition of new equip- ment high on the telescope required additional coun- terbalance weights for the telescope. These weights were designed and added in sequence; doing so allowed us to install the laser components (GNEST and EC) while maintaining telescope bal- ance through the day (July 19th). We then installed the utilities and services for the laser. Testing began with power on August 16th, followed by first open-beam verifica- tion on the 22nd. Laser alignment through the optical path to the Beam Transfer Op- tics Optical Bench on the secondary was verified, allowing us to conduct our first on- sky propagation at zenith on August 31st. Gemini Optical Engineer Tom Schneider prepares insulation for GNEST (laser housing designed for our TOPTICA laser head and optical bench). Figure 7 (above center). Gemini senior optical technician Clayton Ah Hee (left, in foreground) and Gemini summit crew member John Randrup prepare GNEST for installation onto telescope. Figure 8 (above right). Verifying laser alignment through the optical path to the Beam Transfer Optics Optical Bench on the secondary. The GN laser design allowed the cre- ation of a single housing for both the laser head and Beam Injection Module Optical Bench. We refer to the housing as GNEST (Gemini North Enclosure Sys- tem for TOPTICA). The laser head with- in the GNEST is coupled to the TOPTI- CA Electronics Cabinet (EC) by optical fibers and communication cabling. We maintained the fiber coupling during installation, which was quite demand- October 2018 Figure 6 (above left). Figure 9 (bottom right). Installing GNEST onto telescope truss below top ring. Credit: All photos this page by Jeff Donahue GeminiFocus 19