Héctor Vázquez Ramió

European Extremely Large Telescope Site Characterization I: Overview

ABSTRACT.The site for the future European Extremely Large Telescope (E-ELT) is already known to be Armazones, near Paranal (Chile). The selection was based on a variety of considerations, with an important one being the quality of the atmosphere for the astronomy planned for the ELT. We present an overview of the characterization of the atmospheric parameters of candidate sites, making use of standard procedures and instruments as carried out within the Framework Programme VI (FP6) of the European Union. We have achieved full characterization of the selected sites for the parameters considered. Further details on adaptive optics results and climatology will be the subject of two forthcoming articles. A summary of the results of the FP6 site-testing campaigns at the different sites is provided.

European Extremely Large Telescope Site Characterization. II. High Angular Resolution Parameters

ABSTRACT.This is the second article of a series devoted to European Extremely Large Telescope (E-ELT) site characterization. In this article we present the main properties of the parameters involved in high angular resolution observations from the data collected in the site testing campaign of the E-ELT during the design study (DS) phase. Observations were made in 2008 and 2009, in the four sites selected to shelter the future E-ELT (characterized under the ELT-DS contract): Aklim mountain in Morocco, Observatorio del Roque de los Muchachos (ORM) in Spain, Macon range in Argentina, and Cerro Ventarrones in Chile. The same techniques, instruments, and acquisition procedures were taken on each site. A multiple aperture scintillation sensor (MASS) and a differential image motion monitor (DIMM) were installed at each site. Global statistics of the integrated seeing, the free atmosphere seeing, the boundary layer seeing, and the isoplanatic angle were studied for each site, and the results are presented here. ...

European Extremely Large Telescope Site Characterization III: Ground Meteorology

Both meteorology and optical conditions are crucial for selecting the best site to host extremely large telescopes such as the Thirty Meter Telescope (TMT) and the European project (E-ELT). For the E-ELT, a year-long meteorological campaign was performed at our two reference sites, the Observatorio del Roque de los Muchachos (ORM) and Cerro Ventarrones (very close to the VLT site at Paranal), and at other sites also considered as alternatives to the reference sites: Aklim, Macon, and Izana (Observatorio del Teide; OT). In this article, we present a statistical analysis of the ground meteorological properties recorded at these sites, making use of automatic weather stations (AWSs) equipped with standard meteorological sensors providing the air temperature, relative humidity, barometric pressure, wind speed, and wind direction, using standard procedures across all sites. Meteorology offers but one discriminant in the complicated question of where to site such a major facility as the E-ELT (other factors being seeing, local geology, the economics of the logistics, etc.), both for determining the feasibility of telescope and instrumentation design and construction and for determining the useful observing time. However, the final decision of where to locate a major telescope depends in part on all these—and other—considerations and not on any one criterion alone. In summary, for 90% of the nighttime, the wind speed is lower than 18 m s-1, the telescope operational limit at all the sites except Macon. For this reason, Macon was discarded in the final site selection as, for 25% of the time, the wind speed is greater than 17 m s-1. The smallest nighttime temperature gradient is at ORM, whereas the lowest mean relative humidity value is reached at the Ventarrones site. Izana was discarded in the site selection study from the very beginning due to lack of funding to install further site-testing equipement (e.g., Multi-Aperture Scintillation Sensor-Differential Image Motion Monitor (MASS-DIMM)). We investigate the statistical distributions of annual and monthly meteorological conditions for day and night separately. This is the third paper in a series discussing the E-ELT FP6 site characterization project.

Robotic operation of the Observatorio Astrofísico de Javalambre (OAJ)

The Observatorio Astrofísico de Javalambre (OAJ) is a fully automated astronomical observatory located at the Sierra de Javalambre (Teruel, Spain) whose primary role is to conduct all-sky astronomical surveys with two unprecedented telescopes of unusually large fields of view: the JST/T250, a 2.55m telescope of 3deg field of view, and the JAST/T80, an 83cm telescope of 2deg field of view. The OAJ control system based on CIA model is a global tool to manage, monitor, control and maintain all observatory systems including not only astronomical subsystems but also infrastructure and other facilities. The OCS deployment is a standards-based development, taking advantage of technologies such as EPICS framework, EtherCAT Fieldbus and Beckhoff PLC hardware as open automation systems based on PC Control technology. The present paper describes the deployment of the OCS architecture, current status of the implementation, lessons learned and stimulating results of J-PLUS survey performed with JAST/T80 telescope, the open access to the Early Data Release (EDR) of the Javalambre Photometric Local Universe Survey and next steps with JST/T250 telescope and J-PAS Javalambre Physics of the Accelerating Universe Astrophysical Survey.

OAJ 2.6m survey telescope: optical alignment and on-sky evaluation of IQ performances

AMOS has recently completed the alignment campaign of the 2.6m telescope for the Observatorio Astrofisico de Javalambre (OAJ). AMOS developed an innovative alignment technique for wide field-of-view telescopes that has been successfully implemented on the OAJ 2.6m telescope with the active support of the team of CEFCA (Centro de Estudios de Física del Cosmos de Aragón). The alignment relies on two fundamental techniques: (1) the wavefront-curvature sensing (WCS) for the evaluation of the telescope aberrations at arbitrary locations in the focal plane, and (2) the comafree point method for the adjustment of the position of the secondary mirror (M2) and of the focal plane (FP). The alignment campaign unfolds in three steps: (a) analysis of the repeatability of the WCS measurements, (b) assessment of the sensitivity of telescope wavefront error to M2 and FP position adjustments, and (c) optical alignment of the telescope. At the end of the campaign, seeing-limited performances are demonstrated in the complete focal plane. With the help of CEFCA team, the image quality of the telescope are investigated with a lucky-imaging method. Image sizes of less than 0.3 arcsec FWHM are obtained, and this excellent image quality is observed over the complete focal plane.

Design and performance of the Paranal cute-SCIDAR instrument for real-time turbulence profiles measurements

We present in this paper the new cute-SCIDAR instrument, entirely developed by the Instituto de Astrofísica de Canarias (IAC), delivered recently at the European Southern Observatory (ESO) Paranal Observatory (Chile). This instrument, supported by the European Community (Framework Programme 6, Extremely Large Telescope Design Study), carries out the generalized SCIntillation Detection And Ranging (g-SCIDAR) technique to obtain the temporal evolution of turbulence profiles CN 2 with height. A new design was made in order to fit the VLT Auxiliary Telescopes (ATs) interfaces and control requirements. Also, a new software architecture allows a full remote control, and a data analysis pipeline provides turbulence profiles in real-time, which is the main achievement of this new cute-SCIDAR. Details of its design and results of its excellent performance are included.

The hybrid Shack-Hartmann/G-SCIDAR instrument

We have built a hybrid turbulence profiler measuring simultaneously the atmospheric turbulence structure with a Shack- Hartmann wave front sensor and a G-SCIDAR (scintillation sensor). This is the first instrument combining two different techniques to measure simultaneously the turbulence structure. The hybrid profiler has been installed at the Carlos Sánchez Telescope (TCS) at the Teide Observatory (OT), in Tenerife Spain. The G-SCIDAR arm is already working properly and we are still testing the Shack-Hartmann arm.

The Observatorio Astrofísico de Javalambre: engineering for empowering observatory operations

The Observatorio Astrofísico de Javalambre is a fully automated astronomical observatory particularly conceived for carrying out large sky surveys with two unprecedented telescopes of unusually large fields of view: the JST/T250, a 2.55m telescope of 3deg field of view, and the JAST/T80, an 83cm telescope of 2deg field of view. The most immediate objective of the two telescopes for the next years is carrying out two unique photometric surveys of several thousands square degrees, Javalambre Phtometry of the Accelerating universe Survey (J-PAS) and Javalambre Photometry of the Local Universe Survey (J-PLUS), each of them with a wide range of scientific applications, like e.g. large structure cosmology and dark energy, galaxy evolution, supernovae, Milky Way structure, among others. To do that, JST and JAST will be equipped with panoramic cameras under development within the J-PAS collaboration, JPCam and T80Cam respectively, which make use of large format (~ 10k x 10k) CCDs covering the entire focal plane. This paper describes in detail, from operations point of view, the engineering development of the overall facilities and infrastructures for the robotic observatory and a global overview of current status pinpointing lessons learned in order to boost observatory operations performance achieving scientific targets, maintaining quality requirements but also minimizing resources, material and human resources. We also briefly introduce the Early Data Release (EDR) of J-PLUS, which is already freely accessible worldwide, and the first scientific papers. Finally, we show the next steps necessary for JST to perform the J-PAS project.

Making a robust, reliable, and a highly available DIMM seeing monitor

During the last 20 years, many DIMM instruments have been developed to measure astronomical seeing. The IAC has been involved in several projects to run different campaigns to characterize its observatories. However, the cost in manpower to maintain and operate these instruments has been too high and it is mandatory to minimize this effort by constructing a reliable, robust and available seeing monitor. A review of all sources of errors has been done in order to fit very reliable measurements: acquisition parameters, box size, signal threshold, SNR threshold, flux, deformations and vibrations for centroid calculations, best pixel scale, jitter in the images sampling, light bandwidth, CCD noise, as well as the centroid calculation algorithm. Experimental measurements about the influence of exposure time, number of images for computing the seeing or defocus have been carried out to identify the practical limits of the instrument. The IAC automatic DIMM design has been reviewed to improve its robustness and its availability to guarantee the minimum down-time and to maximize the time between failures. The new design will be shown as part of this work.