E. Anaclerio

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Istituto Nazionale di Astrofisica, FIRENZE, ITALY

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Utah Valley University

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Papers by E. Anaclerio

LBT adaptive secondary preliminary design

Storage and Retrieval for Image and Video Databases, 2000

We report on the design of the two Gregorian adaptive secondary mirrors of the Large Binocular Te... more We report on the design of the two Gregorian adaptive secondary mirrors of the Large Binocular Telescope. Each adaptive secondary is a Zerodur shell having an external diameter of 911 mm and a thickness of about 1.5 mm. The deformable mirror is controlled by a pattern of 918 electromagnetic actuators. Its shape is referred to a stable ULE back plate

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Delivery of the Second Generation VLT Secondary Mirror (M2) Unit to ESO

The deformable secondary mirror (DSM), one of the key systems of the VLT Adaptive Optics Facility... more The deformable secondary mirror (DSM), one of the key systems of the VLT Adaptive Optics Facility (AOF), has been delivered to ESO. It has been fully qualified in standalone mode and has successfully passed the technical acceptance Europe. Recently it was installed on ASSIST, the test bench for the AOF, and will undergo optical tests, which will complete its preliminary acceptance in Europe. With its 1170 actuators and 1.1-metre thin-shell mirror, it constitutes the largest adaptive optics mirror ever produced. The DSM constitutes a fine accomplishment by European industry and is set to become the "flagship" of the AOF on Paranal.

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Voice-coil technology for the E-ELT M4 Adaptive Unit

1st AO4ELT conference - Adaptive Optics for Extremely Large Telescopes, 2010

We present our design of the E-ELT M4 Adaptive Unit based on voice-coil driven deformable mirror ... more We present our design of the E-ELT M4 Adaptive Unit based on voice-coil driven deformable mirror technology. This technology was developed by INAF-Arcetri, Microgate and ADS team in the past 15 years and it has been adopted by a number of large ground based telescopes as the MMT, LBT, Magellan and lastly the VLT in the frame of the Adaptive Telescope Facility project. Our design is based on contactless force actuators made by permanent magnets glued on the back of the deformable mirror and coils mounted on a stiff reference structure. We use capacitive sensors to close a position loop co-located with each actuator. Dedicated high performance parallel processors are used to implement the local de-centralized control at actuator level and a centralized feed-forward computation of all the actuators forces. This allowed achieving in our previous systems dynamic performances well in line with the requirements of the M4 Adaptive Unit (M4AU) case. The actuator density of our design is in the order of 30-mm spacing for a figure of about 6000 actuators on the M4AU and it allows fulfilling the fitting error and corrections requirements of the E-ELT high order DM. Moreover, our contact-less technology makes the Deformable Mirror tolerant to up 5% actuators failures without spoiling system capability to reach its specified performances, besides allowing large mechanical tolerances between the reference structure and the deformable mirror. Finally, we present the Demonstration Prototype we are building in the frame of the M4AU Phase B study to measure the optical dynamical performances predicted by our design. Such a prototype will be fully representative of the M4AU features, in particular it will address the controllability of two adjacent segments of the 2-mm thick mirror and implement the actuators "brick" modular concept that has been adopted to dramatically improve the maintainability of the final unit.

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VLT deformable secondary mirror: integration and electromechanical tests results

Adaptive Optics Systems III, 2012

ABSTRACT The VLT Deformable secondary is planned to be installed on the VLT UT#4 as part of the t... more ABSTRACT The VLT Deformable secondary is planned to be installed on the VLT UT#4 as part of the telescope conversion into the Adaptive Optics test Facility (AOF). The adaptive unit is based on the well proven contactless, voice coil motor technology that has been already successfully implemented in the MMT, LBT and Magellan adaptive secondaries, and is considered a promising technical choice for the forthcoming ELT-generation adaptive correctors, like the E-ELT M4 and the GMT ASM. The VLT adaptive unit has been recently assembled after the completion of the manufacturing and modular test phases. In this paper, we present the most relevant aspects of the system integration and report the preliminary results of the electromechanical tests performed on the unit. This test campaign is a typical major step foreseen in all similar systems built so far: thanks to the metrology embedded in the system, that allows generating time-dependent stimuli and recording in real time the position of the controlled mirror on all actuators, typical dynamic response quality parameters like modal settling time, overshoot and following error can be acquired without employing optical measurements. In this way the system dynamic and some aspect of its thermal and long term stability can be fully characterized before starting the optical tests and calibrations.

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<title>The VST secondary mirror support system</title>

Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 2008

The VST telescope is equipped with an active optics system based on a wavefront sensor, a set of ... more The VST telescope is equipped with an active optics system based on a wavefront sensor, a set of axial actuators to change the primary mirror shape and a secondary mirror positioner stage. The secondary mirror positioning capability allows the correction of defocus and coma optical aberrations, mainly caused by incorrect relative positions of the optics. The secondary mirror positioner is

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Large Binocular Telescope pre-assembly

Proceedings of …, 2000

The Large Binocular Telescope is currently in the pre-assembly phase at the Ansaldo Energia works... more The Large Binocular Telescope is currently in the pre-assembly phase at the Ansaldo Energia workshop in Milan. Since late 1998 the manufacturing of the Azimuth and Elevation structures has been taken place in North Italy along with the main auxiliary equipments, ...

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<title>The adaptive secondary mirror for the Large Binocular Telescope: optical acceptance test and preliminary on-sky commissioning results</title>

Adaptive Optics Systems II, 2010

The Large Binocular Telescope (LBT) has two adaptive secondary mirrors based on 672 voice-coil fo... more The Large Binocular Telescope (LBT) has two adaptive secondary mirrors based on 672 voice-coil force actuators. The shape of the mirror is controlled using internal metrology based on co-located capacitive sensors. The first mirror unit is currently mounted on LBT for on-sky commissioning as part of the First Light Adaptive Optics System (FLAO). During spring-time 2009 the optical acceptance test was performed using the 14-m optical test tower at the Osservatorio Astrofisico di Arcetri (INAF) showing the capability of flattening the shell at the level of 14nm rms residual surface error. This paper reports the optical layout, calibration procedures and results of the optical acceptance test. Moreover we report the first results obtained during the early runs of FLAO commissioning showing the ability of the mirror to compensate for atmospheric turbulence with extremely high Strehl ratio values (better than 80% in H-band) as permitted by the largest number of correcting degrees of freedom currently available on-sky for astronomical telescopes.

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