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Proceedings Paper

Dark Energy Camera installation at CTIO: technical challenges
Author(s): Freddy Muñoz A.; Andrés Montane; Roberto Tighe; Michael Warner; Timothy M. Abbott
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Paper Abstract

The Dark Energy Camera (DECam) is a new prime focus, wide-field imager for the V. M. Blanco 4-m telescope at CTIO. Instrumentation includes large, five-lens optical corrector mounted on hexapod mechanism for fine adjustment, filters, and a 519 Megapixel camera vessel; all integrated in a cage similar to the existing telescope prime focus structure. Currently Blanco allows a flip of this structure such that the f/8 secondary mirror, mounted on the back of the cage, points towards the primary mirror for Ritchey-Chretien observations. DECam will maintain this capability by attaching the existing F/8 mirror cell to the front of the new cage. Installation of this 8,600 kg instrument required the removal from the telescope of the primary mirror, the removal of the old prime focus assembly, and fine adjustment of large, over-constrained mechanisms followed by reassembly. A large facility shutdown was scheduled for this upgrade and several tools, fixtures, monitoring systems and procedures were developed in order to identify and then recover the optical alignment of the system, to control the distribution of stresses during tuning of the installation and to maintain the balance of the telescope with significant added mass. The final goal has been to maintain high performance of the telescope for both the existing f/8 Ritchey-Chretien focus mounted instruments and the new DECam instrument now in commissioning. The challenges presented in handling large elements, real-time monitoring, alignment, verification and feedback are described.

Paper Details

Date Published: 17 September 2012
PDF: 12 pages
Proc. SPIE 8444, Ground-based and Airborne Telescopes IV, 844446 (17 September 2012); doi: 10.1117/12.925752
Show Author Affiliations
Freddy Muñoz A., Cerro Tololo Inter-American Observatory (Chile)
Andrés Montane, Cerro Tololo Inter-American Observatory (Chile)
Roberto Tighe, Cerro Tololo Inter-American Observatory (Chile)
Michael Warner, Cerro Tololo Inter-American Observatory (Chile)
Timothy M. Abbott, Cerro Tololo Inter-American Observatory (Chile)

Published in SPIE Proceedings Vol. 8444:
Ground-based and Airborne Telescopes IV
Larry M. Stepp; Roberto Gilmozzi; Helen J. Hall, Editor(s)

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