
Proceedings Paper
Experiences with global laser tracker alignment of the 32.5-m LMT primary surfaceFormat | Member Price | Non-Member Price |
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Paper Abstract
The Large Millimeter Telescope Alfonso Serrano (LMT) currently has a primary reflector of 32.5m diameter composed
of 84 panels, each having a surface area of approximately 10 square meters. Each panel is supported on four electromechanical
actuators, allowing for the correction of tip-tilt, piston and twist. The actuators are designed to perform active
surface compensation of gravity deformations as a function of elevation.
Following the setting and installation of individual panels, an approximation for global alignment of the primary surface
is carried out using a total station. An RMS error of 200 - 500μm is expected for this process. Final global alignment is
conducted using holography at 12GHz for elevations corresponding to the location of geostationary sources. As an
intermediate alignment option for the antenna at zenith, the use of a laser tracker has been explored. Global alignment of
a large primary surface with a laser tracker presents the common problems related to the contact measurement of a large
object in a non-metrology environment. Key issues are the stable location of fiducial points and the relatively slow data
collection rate. Additionally the high altitude site (4600m, 15000ft) with mean temperatures around zero degrees Celsius,
presents a challenge for our interferometer-equipped trackers.
In this paper we present first results using a tracker located near the antenna vertex, and mechanical adjusters in place of
actuators. An RMS error of around 100μm was achieved. Limiting factors included inadequate fiducials and slow
mapping speed. Proposals for reduced data collection times and improved metrology robustness are presented.
Paper Details
Date Published: 28 July 2014
PDF: 13 pages
Proc. SPIE 9151, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation, 91513Q (28 July 2014); doi: 10.1117/12.2056856
Published in SPIE Proceedings Vol. 9151:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation
Ramón Navarro; Colin R. Cunningham; Allison A. Barto, Editor(s)
PDF: 13 pages
Proc. SPIE 9151, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation, 91513Q (28 July 2014); doi: 10.1117/12.2056856
Show Author Affiliations
Andrea Leon-Huerta, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Maribel Lucero Alvarez, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Emilio Hernández Rios, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Lizeth Cabrera Cuevas, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
David Castro Santos, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Carlos Tzile Torres, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Maribel Lucero Alvarez, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Emilio Hernández Rios, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Lizeth Cabrera Cuevas, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
David Castro Santos, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Carlos Tzile Torres, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Josefina Lázaro Hernández, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
David M. Gale, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Gopal Narayanan, Univ. of Massachusetts Amherst (United States)
David R. Smith, MERLAB, P.C. (United States)
Grant Wilson, Univ. of Massachusetts Amherst (United States)
David M. Gale, Gran Telescopio Milimétrico, Instituto Nacional de Astrofísica, Óptica y Electrónica (Mexico)
Gopal Narayanan, Univ. of Massachusetts Amherst (United States)
David R. Smith, MERLAB, P.C. (United States)
Grant Wilson, Univ. of Massachusetts Amherst (United States)
Published in SPIE Proceedings Vol. 9151:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation
Ramón Navarro; Colin R. Cunningham; Allison A. Barto, Editor(s)
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