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)     

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)     

A protocol standard for heterogeneous telescope networks

The scientific need for a standard protocol permitting the exchange of generic observing services is rapidly escalating as more observatories adopt service observing as a standard operating mode and as more remote or robotic telescopes are brought on‐line. To respond to this need, we present the results of the first interoperability workshop for Heterogeneous Telescope Networks (HTN) held in Exeter. We present a draft protocol, designed to be independent of the specific instrumentation and software that controls the remote and/or robotic telescopes, allowing these telescopes to appear to the user with a unified interface despite any underlying architectural differences. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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)     

Heterogenous telescope networks: An introduction

The first Heterogenous Telescopes Network (HTN) conference was held in July 2005. It aimed to bring together software developers, observatory staff and science users with the objective of defining the how and why of developing new ways of doing astronomical observing using geographically distributed and differently instrumented and operated telescopes. The papers included in this volume arise from that conference. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A Study on the Paul-Baker System as an Instrument for Multi-object Spectrum Observation

Paul-Baker systems with 4°flat field and 5°flat field are studied. Their light obstructions under different f/ratios of the primary mirror are analyzed. Due to the strong f/ratio of the system, a focal length extender is designed in order to match the following fiber instrumentation, and two kinds of dispersion prism correctors are designed for correcting the atmospheric dispersion. We compare the designed Paul-Baker system with LAMOST, the national major scientific project now under construction.     

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)     

STK: A new CCD camera at the University Observatory Jena

The Schmidt‐Teleskop‐Kamera (STK) is a new CCD‐imager, which is operated since begin of 2009 at the University Observatory Jena. This article describes the main characteristics of the new camera. The properties of the STK detector, the astrometry and image quality of the STK, as well as its detection limits at the 0.9 m telescope of the University Observatory Jena are presented (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The NST: First results and some lessons for ATST and EST

In January 2009, first light observations with the NST (New Solar Telescope) in Big Bear Solar Observatory (BBSO) were made. NST has a 1.7 m primary with a 1.6 m clear aperture. First observational results in TiO and Hα are shown and discussed. The NST primary mirror is the most aspheric telescope mirror deployed to date. The NST is early in its commissioning, and the plans for this phase will be sketched. Lessons learned in building and implementing the NST are germane for the ATST and EST telescopes and will be discussed. The NST has an off‐axis Gregorian configuration consisting of a parabolic primary, heat‐stop, elliptical secondary and diagonal flats. The focal ratio of the primary mirror is f/2.4. The working wavelength range covers from 0.4 to 1.7 µm in the Coudé Lab beneath the telescope and all wavelengths including the far infrared at the Nasmyth focus on the dome floor (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

New challenges for adaptive optics: extremely large telescopes

The performance of an adaptive optics (AO) system on a 100-m diameter ground-based telescope working in the visible range of the spectrum is computed using an analytical approach. The target Strehl ratio of 60 per cent is achieved at 0.5 μm with a limiting magnitude of the AO guide source near R   magnitude~10, at the cost of an extremely low sky coverage. To alleviate this problem, the concept of tomographic wavefront sensing in a wider field of view using either natural guide stars (NGS) or laser guide stars (LGS) is investigated. These methods use three or four reference sources and up to three deformable mirrors, which increase up to 8-fold the corrected field size (up to 60 arcsec at 0.5 μm). Operation with multiple NGS is limited to the infrared (in the J band this approach yields a sky coverage of 50 per cent with a Strehl ratio of 0.2). The option of open-loop wavefront correction in the visible using several bright NGS is discussed. The LGS approach involves the use of a faint ( R ~22) NGS for low-order correction, which results in a sky coverage of 40 per cent at the Galactic poles in the visible.     

XMM‐Newton operations beyond the 10‐year design lifetime

In preparation for XMM‐Newton operations beyond the 10‐year design lifetime ESA instigated an independent review of all aspects of the mission. Unsurprisingly, the review found that the scientific interest in extending the mission is very high and likely to remain so in the foreseeable future. Most importantly, all the elements of the XMM‐Newton mission were found to be stable and trouble free with sufficient consumables and life‐limited items to allow operations of the mission until at least 2018. The review endorsed the proposal to combine elements of the Flight Control Team with those from INTEGRAL and remove real‐time instrument monitoring from ESAC in order to reduce costs and improve efficiency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Colour equations for UK Schmidt Telescope Tech-Pan film exposures

Kodak Technical Pan (Tech-Pan) film is a standard panchromatic emulsion that was used at the UK 1.2-m Schmidt Telescope (UKST) for a variety of broad-band exposures between 1992 and 2003. However, despite its versatility and frequent use, no formal presentation of its colour-term stability has been provided. A sample of 32 short-exposure Tech-Pan films was specifically acquired in five wavebands with a view to establishing the photometric relationships between Tech-Pan and the equivalent glass-based emulsions previously used. These films have been measured using the SuperCOSMOS measuring machine and the data reduced to provide the appropriate quantitative information. New colour terms relating these measurements to the Cousins photoelectric system are presented. They are shown to be stable, reproducible, generally small and similar to colour terms previously derived for the older emulsions on glass that Tech-Pan effectively replaced. These results give confidence in the use of Tech-Pan photometry from on-line UKST legacy survey archives.     

New designs of survey telescopes

The immediate goal of modern observational astronomy is to monitor continuously the position and brightness of all objects in the sky brighter than ∼24th magnitude. This review describes wide‐field telescopes designed for this task – both existing and planned. Many systems are described for the first time (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Sodium beacon tip–tilt determination with Rayleigh-aided auxiliary telescope technique

The usefulness of tracking the Rayleigh portion of a mesospheric sodium laser guide star as reference for absolute tip–tilt recovery in the frame of the auxiliary telescopes technique is shown. This approach leads to the reduction of the ground occupation needed to attain a given sky coverage by more than one order of magnitude. Speed, tracking precision, and the number of auxiliary telescopes are also reduced, making this new approach a more attractive one. The use of a low-altitude Rayleigh spot reinforces the fundamental limitations affecting this and other techniques, thus degrading significantly the quality of the recovered tip–tilt. However, it is shown that, provided adequate care is taken in the collection and treatment of data, an interesting tilt signal can still be retrieved.     

GREGOR solar telescope: Design and status

The integration and verification phase of the GREGOR telescope reached an important milestone with the installation of the interim 1 m SolarLite primary mirror. This was the first time that the entire light path had seen sunlight. Since then extensive testing of the telescope and its subsystems has been carried out. The integration and verification phase will culminate with the delivery and installation of the final 1.5 m Zerodur primary mirror in the summer of 2010. Observatory level tests and science verification will commence in the second half of 2010 and in 2011. This phase includes testing of the main optics, adaptive optics, cooling and pointing systems. In addition, assuming the viewpoint of a typical user, various observational modes of the GREGOR Fabry‐Pérot Interferometer (GFPI), the Grating Infrared Spectrograph (GRIS), and high‐speed camera systems will be tested to evaluate if they match the expectations and science requirements. This ensures that GREGOR will provide high‐quality observations with its combination of (multi‐conjugate) adaptive optics and advanced post‐focus instruments. Routine observations are expected for 2012 (© 2010 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)