Preparing the GREGOR solar telescope for night‐time use: Deriving a pointing model

We report on the results of a dedicated campaign to derive a pointing model for the GREGOR solar telescope which took place in December 2011. Two main goals were in the focus of this campaign: first to prove the aptness of the GREGOR solar telescope for night‐time, unattended operations and second to derive some qualitative measure of the amount of misalignment in the optical and mechanical parts of the telescope. In the final version, a root‐mean‐square deviation (RMSD) of 1.6″ for the azimuth model and an RMSD of 2.3″ in the elevation model could be achieved (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Scheduling for Robonet‐1 homogenous telescope network

The Robonet‐1 homogenous telescope network consists of 3 fully robotic 2 m class telescopes. I describe how the observation requests submitted by external users and automated user agents are selected for observation by the individual telescope schedulers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Low‐frequency heliographic observations of the quiet Sun corona

We present new results of heliographic observations of quiet‐Sun radio emission fulfilled by the UTR‐2 radio telescope. The solar corona investigations have been made close to the last solar minimum (Cycle 23) in the late August and early September of 2010 by means of the two‐dimensional heliograph within 16.5–33 MHz. Moreover, the UTR‐2 radio telescope was used also as an 1‐D heliograph for one‐dimensional scanning of the Sun at the beginning of September 2010 as well as in short‐time observational campaigns in April and August of 2012. The average values of integral flux density of the undisturbed Sun continuum emission at different frequencies have been found. Using the data, we have determined the spectral index of quiet‐Sun radio emission in the range 16.5–200 MHz. It is equal to –2.1±0.1. The brightness distribution maps of outer solar corona at frequencies 20.0 MHz and 26.0 MHz have been obtained. The angular sizes of radio Sun were estimated. It is found that the solar corona at these frequencies is stretched‐out along equatorial direction. The coefficient of corona ellipticity varies slightly during above period. Its mean magnitudes are equal to ≈ 0.75 and ≈ 0.73 at 20.0 MHz and 26.0 MHz, respectively. The presented results for continuum emission of solar corona conform with being ones at higher frequencies. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Autonomous software: Myth or magic?

We discuss work by the eSTAR project which demonstrates a fully closed loop autonomous system for the follow up of possible micro‐lensing anomalies. Not only are the initial micro‐lensing detections followed up in real time, but ongoing events are prioritised and continually monitored, with the returned data being analysed automatically. If the “smart software” running the observing campaign detects a planet‐like anomaly, further follow‐up will be scheduled autonomously and other telescopes and telescope networks alerted to the possible planetary detection.We further discuss the implications of this, and how such projects can be used to build more general autonomous observing and control systems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Field optimization and CCD data simulation for the antarctic International Concordia Explorer Telescope (ICE‐T)

We performed extensive data simulations for the planned ultra‐wide‐field, high‐precision photometric telescope ICE‐T (International Concordia Explorer Telescope). ICE‐T consists of two 60 cm‐aperture Schmidt telescopes with a joint field of view simultaneously in two photometric bandpasses. Two CCD cameras, each with a single 10.3k × 10.3k thinned back‐illuminated device, would image a sky field of 65 square degrees. Given a location of the telescope at Dome C on the East Antarctic Plateau, we searched for the star fields that best exploit the technical capabilities of the instrument and the site. We considered the effects of diurnal air mass and refraction variations, solar and lunar interference, interstellar absorption, overexposing of bright stars and ghosts, crowding by background stars, and the ratio of dwarf to giant stars in the field. Using NOMAD, SSA, Tycho‐2 and 2MASS‐based stellar positions and BVIJH magnitudes for these fields, we simulated the effects of the telescope's point‐spread‐function, the integration, and the co‐addition times. Simulations of transit light curves are presented for the selected star fields and convolved with the expected instrumental characteristics. For the brightest stars, we showed that ICE‐T should be capable of detecting a 2 R_Earth Super Earth around a G2 solar‐type star, as well as an Earth around an M0‐star – if these targets were as abundant as hot Jupiters. Simultaneously, the telescope would monitor the host star's surface activity in an astrophysically interpretable manner (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Grid integration of robotic telescopes

Robotic telescopes and grid technology have made significant progress in recent years. Both innovations offer important advantages over conventional technologies, particularly in combination with one another. Here, we introduce robotic telescopes used by the Astrophysical Institute Potsdam as ideal instruments for building a robotic telescope network. We also discuss the grid architecture and protocols facilitating the network integration that is being developed by the German AstroGrid‐D project. Finally, we present three user interfaces employed for this purpose. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

An RTML transport implementation on the Liverpool Telescope

The Liverpool Telescope is a 2.0m fully robotic telescope based on the Canary island of LaPalma. In this paper I describe the Java(TM) implementation of a method to transport RTML (Remote Telescope Markup Language) between a Node Agent (Web Services endpoint) embedded at the telescope and a remote Agent. The advantages and disadvantages of the method are discussed, along with the suitability of the protocol for HTN standardisation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Robonet‐1.0

Robonet‐1.0 is a prototype network of 2m robotic telescopes spread out around the world, consisting of three 2 metre telescopes. In this paper we present some of the science done with the network and how we use eSTAR and HTN technologies to perform observing programmes in an efficient manner. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Architectures for science: Intelligent agent technology

I review the current architecture of the HTN and make three suggestions for the future. (i) We should retain the expertise split between agents which deal with the science programmes and those which deal with telescope constraints. This makes it easy to add new programmes or new telescopes. (ii) We should develop “look ahead” schedulers which attempt to schedule a whole night at once. This will give reliable calculations for the chance an observation will be carried out, and give a better chance that high priority time critical observations are successfully scheduled. (iii)We should strive to attract more science programmes to the HTN, in particular time critical observations spread over many nights, and non‐time critical work which can benefit from access to databases and the literature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The eSTAR network – agent architectures for astronomy

The eSTAR Project uses intelligent agent technologies to carry out resource discovery, submit observation requests and analyze the reduced data returned from a meta‐network of robotic telescopes. Linking ground based telescopes with astronomical satellites, and using the emerging field of intelligent agent architectures to provide crucial autonomous decision making in software, the project has succeeded in combining data archives and research class telescopes, along with distributed computing nodes, to build an ad‐hoc peer‐to‐peer heterogeneous network of resources. We present the current operations paradigm of the eSTAR network and describe the direction in which the project intends to develop over the next few years. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Pointing and tracking analysis of alt‐azimuthal multi‐focus telescopes: the THEMIS case

We discuss the pointing and tracking configuration of THEMIS which may be considered as representative of those alt‐azimuthal telescopes with an optical configuration with multiple focal planes, not all locked to both the alt‐azimuthal coordinates. In the THEMIS case two focal planes are present. The primary focus F1 is locked to the alt‐azimuthal mount, while the secondary focus F2 (which is used by the instruments), is only locked to the azimuth angle. The different contributions to the final accuracy of both absolute pointing and tracking as observed at F2 are defined, and an extimation of the contribution of each component of the whole chain which affects the field position at F2 (software, mechanical and optical) is given. The experimental data are the result of a test campaign carried on at THEMIS in February and March 2002. We can say that (a) for all the used observing configurations, the tracking accuracy is coherent at any point along the trajectory with the correspondent absolute pointing accuracy, which is an indication for the quality of the telescope dynamical performances (b) the main contribution to the residual field shift which is observed at F2 arises from the opto‐mechanical alignment configuration of the optics between F1 and F2, which therefore is the crucial point for such multi‐focus configuration. More informations can be found at the official THEMIS website (http://www.themis.iac.es).     

Automated probabilistic classification of transients and variables

There is an increasing number of large, digital, synoptic sky surveys, in which repeated observations are obtained over large areas of the sky in multiple epochs. Likewise, there is a growth in the number of (often automated or robotic) follow‐up facilities with varied capabilities in terms of instruments, depth, cadence, wavelengths, etc., most of which are geared toward some specific astrophysical phenomenon. As the number of detected transient events grows, an automated, probabilistic classification of the detected variables and transients becomes increasingly important, so that an optimal use can be made of follow‐up facilities, without unnecessary duplication of effort. We describe a methodology now under development for a prototype event classification system; it involves Bayesian and Machine Learning classifiers, automated incorporation of feedback from follow‐up observations, and discriminated or directed follow‐up requests. This type of methodology may be essential for the massive synoptic sky surveys in the future. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Precovery of near‐Earth asteroids by a citizen‐science project of the Spanish Virtual Observatory

This article describes a citizen‐science project conducted by the Spanish Virtual Observatory (SVO) to improve the orbits of near‐Earth asteroids (NEAs) using data from astronomical archives. The list of NEAs maintained at the Minor Planet Center (MPC) is checked daily to identify new objects or changes in the orbital parameters of already catalogued objects. Using NEODyS we compute the position and magnitude of these objects at the observing epochs of the 938 046 images comprising the Eigth Data Release of the Sloan Digitised Sky Survey (SDSS). If the object lies within the image bound‐aries and the magnitude is brighter than the limiting magnitude, then the associated image is visually inspected by the project's collaborators (the citizens) to confirm or discard the presence of the NEA. If confirmed, accurate coordinates and, sometimes, magnitudes are submitted to the MPC. Using this methodology, 3226 registered users have made during the first fifteen months of the project more than 167 000 measurements which have improved the orbital elements of 551 NEAs (6% of the total number of this type of asteroids). Even more remarkable is the fact that these results have been obtained at zero cost to telescope time as NEAs were serendipitously observed while the survey was being carried out. This demonstrates the enormous scientific potential hidden in astronomical archives. The great reception of the project as well as the results obtained makes it a valuable and reliable tool for improving the orbital parameters of near‐Earth asteroids. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Multi‐frequency solar observations at Metsähovi Radio Observatory and KAIRA

We describe solar observations carried out for the first time jointly with Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) and Aalto University Metshovi Radio Observatory (MRO). KAIRA is new radio antenna array observing the decimeter and meter wavelength range. It is located near Kilpisjärvi, Finland, and operated by the SodankyläGeophysical Observatory, University of Oulu. We investigate the feasibility of KAIRA for solar observations, and the additional benefits of carrying out multi‐instrument solar observations with KAIRA and the MRO facilities, which are already used for regular solar observations. The data measured with three instruments at MRO, and with KAIRA during time period 2014 April–October were analyzed. One solar radio event, measured on 2014 April 18, was studied in detail. Seven solar flares were recorded with at least two of the three instruments at MRO, and with KAIRA during the chosen time period. KAIRA is a great versatile asset as a new Finnish instrument that can also be used for solar observations. Collaboration observations with MRO instruments and KAIRA enable detailed multi‐frequency solar flare analysis. Flare pulsations, flare statistics and radio spectra of single flares can be investigated due to the broad frequency range observations. The Northern locations of both MRO and KAIRA make as long as 15‐hour unique solar observations possible during summer time. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectro‐polarimetry in the era of large solar telescopes

This paper discusses some of the challenges of spectro‐polarimetric observations with a large aperture solar telescope such as the ATST or the EST. The observer needs to reach a compromise between spatial and spectral resolution, time cadence, and signal‐to‐noise ratio, as only three of those four parameters can be pushed to the limit. Tunable filters and grating spectrographs provide a natural compromise as the former are more suitable for high‐spatial resolution observations while the latter are a better choice when one needs to work with many wavelengths at full spectral resolution. Given the requirements for the new science targeted by these facilities, it is important that 1) tunable filters have some multi‐wavelength capability; and 2) grating spectrographs have some 2D field of view (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

High level interfaces to the Robonet‐1.0 Homogeneous Telescope Network

We describe the current high level interfaces used for communicating with the Robonet‐1.0 Homogeneous Telescope Network. This is a network of three telescopes, the Liverpool Telescope and the Faulkes Telescopes (North and South). We describe our use of RTML and web‐services to enable control of the network by intelligent agents. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The GREGOR telescope control system

This article describes the architecture of the new GREGOR telescope and its instrument control system. A short summary is given on the communication structure between instruments and other devices during observation. Because of its importance to all instruments the main functions of the telescope control system are described in detail (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Astronomical network event and observation notification

Networks are becoming a key element in most current and all future, telescope and observatory projects. The ability to easily and efficiently pass observation data, alert data and instrumentation requests between distributed systems could enable science as never before. However, any effective large scale or meta‐network of astronomical resources will require a common communication format or development resources will have to be continuously dedicated to creating interpreters. The necessary elements of any astronomy communication can be easily identified, efficiently described and rigidly formatted so that both robotic and human operations can use the same data. In this paper we will explore the current state of notification, what notification requirements are essential to create a successful standard and present a standard now under development by the International Virtual Observatory Alliance (IVOA), called the VOEvent. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The new IRSOL solar telescope control system

We would like to present a new control system for the solar telescope now in operation at the Swiss institute, Istituto Ricerche Solari Locarno (IRSOL). The control software is multi‐client capable, and optionally uses the primary image of the sun projected on a position sensor or the axis encoder for guiding. The hardware and software consist of three completely separate levels, which communicate with each other via ASCII commands. We shall describe the general principles implemented in the course of the development. We consider it important that this text is also applicable to other astronomical device controls. Therefore we explain our specific solution next to general principles (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Open‐foldable domes with high‐tension textile membranes: The GREGOR dome

Double layers of high‐tensioned textile membranes were applied to the completely open‐foldable dome for the GREGOR telescope for the first time. Simultaneous climate measurements inside and outside the dome have proven the thermalinsulating capability of this double‐layer construction. The GREGOR dome is the result of the continuation of the ESO research on open‐foldable domes with textile structures, followed by the research for the DOT dome with high‐tensioned textile membranes. It cleared the way to extreme stability required for astronomical practice on high mountain sites with heavy storms and ice formation. The storm Delta with 245 km/h 1‐minute mean maximum at the location of the GREGOR caused no problems, nor did other storms afterwards. Opening and closing experiences up to wind speeds of 90 km/h were without problems. New technical developments were implemented and tested at the GREGOR dome, opening the way for application to much larger domes up to the 30 m diameter‐class range (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)