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ING Annual Report 1998
Previous: Chapter 2 - New Instrumentation and Enhancements | Up: Table of Contents | Next: Chapter 4 - Telescope PerformanceChapter 3
Telescope Operation
TELESCOPES
Telescope operation has enjoyed a year of relative stability with telescope downtime due to technical problems averaging 2.7, 5.2, and 2.3% on the WHT, the INT, and the JKT, respectively. The relatively high down-time on the INT results from having introduced several new control systems as explained further on in this report.
The international collaboration on which our organisation is based was extended in 1998. Following the signing of an international agreement, the University of Porto joined ING in February. As part of this collaboration the University of Porto obtains 28 nights of observing time on the JKT and access to the INT and WHT under open competition with other astronomers through the normal peer review process. The University of Porto has placed personnel at ING in support of telescope operation.
The scientific role of the Isaac Newton Telescope evolved in a substantial way through the initiation of large scale survey observation using the prime focus Wide Field Camera. At its meeting in October 1997 the UK/NL Joint Steering Committee considered a proposal to devote a substantial percentage of observing time on the INT to survey observations. It was considered timely, given the advent of the Wide Field Camera, to exploit this unique instrument extensively, in particular for survey observations serving a wide community of researchers. This new initiative also allowed the telescope to evolve in a way that best serves the new generation of large telescopes. In addition, a severe budgetary constraint on the operation of the ING telescopes forces the observatory to look for more cost-effective ways of running the telescopes. The survey observations provide a step in this direction.
An Announcement of Opportunity was sent out inviting the UK and NL community to propose large-scale survey programmes to be carried out with the Wide Field Camera. This announcement met with a very good response. An independent assessment panel recommended priorities and the amount of observing time that should be devoted to these survey observations. Subsequently observing time was granted on condition that the raw and reduced data should be made available to the UK/NL community as quickly as possible after the observations have been taken, to allow fast exploitation of the unique database.
The Wide Field Survey observations duly commenced in August 1998. The approved programmes cover a wide range of science topics. The largest programme, a wide-angle survey covering more than 100 square degrees in multiple wavebands, will address key issues ranging from the determination of cosmological parameters to the search for Solar System objects. A second programme will take very deep images over a number of selected fields to study the evolution of galaxy clustering, to yield a catalogue of rich galaxy clusters, and to detect significant numbers of quasars. The third programme will study variability of all objects over 100 square degrees of sky at mid-galactic latitudes in support of a wide variety of investigations including stellar population studies, Kuiper Belt objects, and Gamma-ray Bursters.
Modernisation of the general telescope infrastructure passed an important milestone with the installation of a DEC-Alpha based Telescope Control System on all three telescopes, replacing the old computers and software systems. The common platform for the three telescopes has greatly reduced the support effort. A further milestone has been the installation on the JKT of a new Unix based data acquisition system and instrument control system, similar to the one already in operation at the INT. These upgrades have much reduced observing overheads and improved user friendliness of the observing systems. The INT has reached a level of integration where a single person can operate the telescope without much difficulty, and, equally important, through observing scripts the telescope can operate unassisted for extensive periods.
The Faint Object Spectrograph, FOS-2 on the WHT was decommissioned. The main Cassegrain spectrograph, ISIS, already covers most of the functionality offered by FOS-2, and therefore that instrument was no longer competitive.
The primary mirrors of the three telescopes were aluminised in autumn. Regular CO2 snow cleaning of the primary mirrors allows longer periods between aluminising runs and from now on the mirrors will not be aluminised annually. New digital positional sensors were fitted to the WHT mirror cell during the aluminising exercise, which allows re-positioning of the mirror to higher accuracy. Shack-Hartmann tests of the optical quality after the mirror had been re-seated confirmed its successful re-placement.
An extensive campaign to assess the influence of the local environment on the image quality that is delivered at the focus of the WHT was completed during 1998. This campaign comprised regular measurements of the wavefront distortions in the Nasmyth focus, independent 'natural' seeing measurements using a Differential Image Motion Monitor (DIMM), long term monitoring of various meteorological parameters, extensive thermometry within the dome and telescope structure, and analysis of energy dissipation in the building. Over the years many improvements were implemented to protect the dome environment against excessive warming up during the day. The most important impact was the installation during the autumn of 1996 of a more effective bearing oil cooling system that has significantly reduced image degradation within the dome. Analysis of the wave front sensor data and DIMM seeing measurements collected over more than two years have now shown that image degradation arising within the dome introduces a (maximum) image spread of 0.25 arcsec. When added in quadrature to the median year round site seeing of 0.71 arcsec, image degradation caused within the dome contributes no more than 0.1 arcsec to the image spread. The extensive statistics that have been collected on natural seeing at the observatory confirms that the Roque de los Muchachos Observatory enjoys excellent seeing conditions comparable to those of the best sites in the world.
A detailed assessment of ING's susceptibility to the Year 2000 problem was initiated. A risk analysis will be carried out, and solutions will be implemented where necessary. The observing system on the three telescopes will be tested on Year 2000 compliance well before the millennium date change.
The work model for day-to-day operation of the telescopes was substantially changed with the introduction of the Operations Team. This model is designed to provide a better focus on operational engineering duties, and to improve the skill base required for operational duties. The long-term goal is to reduce the number of staff required for operational duties and to make more time available for enhancement and development work.
OBSERVATORY INFRASTRUCTURE
New instruments and large format CCDs, in particular those used in the Wide Field Camera on the INT, have resulted in far greater volumes of data. This development highlighted the urgent need for upgrading the computer network infrastructure and computing power at the observatory. The much larger data rates required a different network topology and improved data handling and storage facilities. New backbone fibre optics cables were installed between the telescopes, data network bottlenecks were cleared by installing local ethernet switches and by resolving network configuration problems. Future steps will include installation of new workstations, servers, backup systems, and data storage capacity.
In support of instrument development work on the new multiple fibre optics unit for AUTOFIB a fibre optics laboratory has been set up in the observatory offices in Santa Cruz. For similar reasons of extended maintenance activities on CCD detectors a well laid-out test facility in the WHT building was completed. Future major development work on detectors and controllers will, however, take place in the observatory building at sea level and in collaboration with the UK ATC.
Following the closure of the Royal Greenwich Observatory in Cambridge, part of the RGO library was transferred to ING. This transfer implies a substantial extension of the existing library, which will be a great benefit to research activities.
The new optics laboratory at the ING sea-level base. [ JPEG | TIFF ]
ING VISITING PANEL REPORT
The UK/NL Joint Steering Committee (JSC) set up an ING visiting Panel to review the operation and development of the ING in order to provide an international and independent perspective on its operation and needs. The Visiting Panel made recommendations to the JSC and the Director of the ING. The Visiting Panel was asked to comment on the international competitiveness of the ING and its likely astronomical prospects in the era of 8-m class telescopes, to review how the ING is organised, and to comment on the requirements for the facility to ensure that the astronomical needs of the user communities in the United Kingdom and the Netherlands are satisfied in the best possible way.
The Visiting Panel constituted of Dr Russell Cannon (Chairman, Anglo-Australian Observatory), Prof Marijn Franx (University of Leiden), Prof Ken Freeman (Mount Stromlo and Siding Spring Observatories), Dr Augustus Oemler (Carnegie Institution of Washington), and Dr Richard Wade (Rutherford Appleton Laboratories).
The report submitted by the Panel touches on many important aspects concerning the current state and future direction of the observatory. The Panel's overall impression is that the ING is functioning as an internationally competitive optical observatory, and that the funding and staffing levels are appropriate for the current programme. Given good management and adequate resources, the ING should be able to maintain its position and continue to make a cost-effective contribution to astronomy in the United Kingdom and the Netherlands. Provided that it is run efficiently, and is equipped with instruments which can compete with or complement those on larger-aperture telescopes, the ING will remain viable indefinitely. To this end, the ING must develop a long-term instrumentation plan, soundly based on astronomical objectives and exploiting the quality of the telescopes and the site. The report stresses that although ING is currently functioning at an appropriate level in comparison with similar international observatories, the ING must find ways to undertake cost-effective cutting-edge science in the era of 8-m telescopes. It also recommended that a larger amount of the resources available to ING be channelled towards development of instrumentation. Possible ways to achieve this are through simplifying telescope operation, and by establishing more suitable facilities at sea level. On the issue of external management the Panel commented that the current arrangements are unwieldy and inefficient, and that a simpler linear structure is needed. The Panel's recommendations were welcomed and endorsed by the JSC and steps are being taken to implement them.
Previous: Chapter 2 - New Instrumentation and Enhancements | Up: Table of Contents | Next: Chapter 4 - Telescope Performance
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