GeminiFocus 2018 Year in Review | Page 62

Figure 5 (above left). The MAROON-X Front End nearing completion at the lab in Chicago. Credit: Andreas Seifahrt Figure 6 (above right). MAROON-X guide camera diagram showing the object fiber in the center (back- illuminated), surrounded by three single-mode fibers. These three fibers allow us to triangulate the position of the object fiber in real time during the observations. A tip-tilt mirror is used to center the stellar image on the object fiber. For lab testing, an “artificial star” was created by placing a pinhole at the nominal telescope focus and illuminating it with an f/16 beam. Two sky fibers, placed 20” from the object fiber in opposite positions, are used to capture the sky background for a high-dispersion spectrum in MAROON-X and for a time-resolved, low-dispersion spectrum with an external spectrograph. A calibration fiber transports light from the spectrograph room to the telescope’s front end and is used to illuminate the object and one of the sky fibers for flatfield and wavelength calibration frames. Credit: Andreas Seifahrt the optical fiber that runs to the instrument and will also include some optics and elec- tronics, as shown in Figure 5. The Front End 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 (Figures 7-10). 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. 60 GeminiFocus The GN laser design allowed the creation 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 System for TOPTICA). The laser head within the GNEST is coupled to the TOPTICA Electronics Cabinet (EC) by op- tical fibers and communication cabling. We maintained the fiber coupling during instal- lation, which was quite demanding logisti- cally and required careful planning. The addition of new equipment high on the telescope required additional counter- balance weights for the telescope. These weights were designed and added in se- quence; doing so allowed us to install the laser components (GNEST and EC) while maintaining telescope balance through the day (July 19th). We then installed the utili- ties and services for the laser. Testing began with power on August 16th, followed by first open-beam verification on the 22nd. Laser alignment through the optical path to the Beam Transfer Optics Optical Bench on the secondary was verified, allowing us January 2019 / 2018 Year in Review