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ING Annual Report 1999
Previous: Chapter 3 - Telescope Operation and Maintenance | Up: Table of Contents | Next: Chapter 5 - In-house Research and Development Activities
Other available formats: PDF | gzipped PostscriptTelescope Performance and Scientific Productivity
Chapter 4
USE OF TELESCOPE TIME
The available observing time on the ING telescopes is allocated between British, Dutch and Spanish time allocation committees, the CCI International Time Programmes (ITP), service and discretionary nights, and scheduled stand-down and commissioning time.
The PPARC-NWO ING Board has delegated the task of time allocation to British astronomers to the PPARC Panel for the Allocation of Telescope Time (PATT), and to Dutch astronomers to the NFRA Programme Committee (PC). On the other hand it is the responsibility of the Astrophysics Institute of the Canaries (IAC) to allocate the Spanish time via the Comité para la Asignación de Tiempos (CAT). The ratio of UK PATT : NL NFRA PC : SP CAT : ITP is nominally 60 : 15 : 20 : 5. This ratio is monitored and small differences in these proportions in any one year are corrected over a number of observing seasons.
The PPARC makes 27 nights per year of its share on the JKT available to the National Board of Science and Technology of Ireland (NBST) and the Dublin Institute for Advanced Studies (DIAS). In a similar way, the University of Porto (Portugal) has 28 nights of observing time on the JKT.
The aim of the ING service programme is to provide astronomers with a way to obtain small sets of observations, which would not justify a whole night or more of telescope time. For each telescope and instrument several nights per month are set aside especially for this purpose. During those nights, ING support astronomers perform observations for several service requests.
Stand-down and discretionary nights are used for major maintenance activities, commissioning, minor enhancements, calibration and quality control tests, etc., and partly for astronomy, for example, as compensation for breakdowns or for observations of targets of opportunity. They are scheduled together with service nights for greater flexibility, but a careful record of service observations per nationality is kept.
The way the available observing time on the ING telescopes has been shared in semesters 99A and 99B is summarised in the table below.
Allocation of time for semesters 99A and 99B WHT INT JKT Nights % Nights % Nights % UK PATT
(includes Irish and Portuguese time on the JKT)163.5 44.8 119.0 32.6 192.0 52.6 NL NFRA PC 41.5 11.4 38.0 10.4 44.0 12.0 SP CAT 55.5 15.2 65.0 17.8 60.0 16.4 UK/NL WFS - - 79.5 21.8 - - ITP 15.0 4.1 16.0 4.4 13.0 3.6 Service/Discretionary
(service nights include UK, NL and SP service time)58.0 15.9 37.5 10.3 33.0 9.1 Commissioning 30.5 8.3 7.0 1.9 18.0 4.9 Stand-down 1.0 0.3 3.0 0.8 5.0 1.4 Total 365.0 100.0 365.0 100.0 365.0 100.0
USE OF INSTRUMENTATION
The tables below show for each telescope the number of nights in semesters 99A and 99B for which the different instruments were scheduled. Stand-down periods are excluded and commissioning nights are shown between parenthesis. The abbreviations are explained in Appendix J. The list of common-user instruments for the same period of time can be found in Appendix B.
As in previous years, the ISIS spectrograph and polarimetre, and UES are the most popular WHT instruments. The improved large CCD detectors available in the WHT prime focus make imaging projects very attractive. Both the AUTOFIB-2 and INTEGRAL fibre units are used in combination with the WYFFOS spectrograph located on the Nasmyth platform. When the telescope is in Nasmyth or Cassegrain configuration, imaging at the Auxiliary Port of the Acquisition and Guidance Unit at the Cassegrain focus is also possible. On the INT, dark time periods are almost exclusively used for CCD imaging with the Wide Field Camera. JKT is a single instrument telescope for CCD imaging.
Allocation of nights per instrument for semesters 99A and 99B
William Herschel Telescope ISIS UES AUTOFIB-2 INTEGRAL PF SAURON ELECTRA LDSS TAURUS S-CAM CIRSI ISIS POL TRIFFID AUX TEIFU Total Nights 137.0 (1.5) 70.4 28.0 24.0 (2.0) 24.0 (2.0) 14.0 (2.5) (14.0) 13.0 8.0 (6.0) 4.0 4.0 4.0 3.1 (2.5) 333.5 (30.5) % 38.1 19.3 7.7 7.1 7.1 4.5 3.8 3.6 2.2 1.7 1.1 1.1 1.1 0.9 0.7 100.0
Isaac Newton Telescope WFC IDS MUSICOS FOS Total Nights 199.0 (3.0) 131.0 (4.0) 19.0 6.0 362.0 % 55.8 37.3 5.2 1.7 100.0
Jacobus Kapteyn Telescope CCD IMAGER Nights 342.0 (18.0) % 100.0
TELESCOPE RELIABILITY
Over semesters 99A and 99B the telescopes performed well, with downtime figures due to technical problems averaging 4.1, 4.5, and 3.5 % on the William Herschel Telescope (WHT), the Isaac Newton Telescope (INT), and the Jacobus Kapteyn Telescope (JKT), respectively. Although technical downtime on the WHT in particular has been somewhat higher than in previous years, these figures meet the target value of a maximum of 5 percent technical downtime.
Weather downtime averaged 28.3, 24.0, and 26.6% on the WHT, INT and JKT respectively over the reporting period. These high figures are due to the exceptionally bad winter 1999–2000.
SCIENTIFIC PRODUCTIVITYThe scientific productivity over 1999 has again been very high with a total of 239 papers published in refereed astronomical journals: 115 for the WHT, 78 for the INT and the remaining 46 for the JKT. The scientific output of the WHT in particular places this telescope amongst the most productive ground-based facilities in the world. Also in terms of ground-breaking discoveries, as published in the journal Nature, the WHT is positioned as a top class facility. A full list of publications is presented in Appendix E.
A study was carried out to assess the scientific productivity of ground-based optical telescopes, comparing the ING telescopes to an international standard. As indicated by the figures above, the ING telescopes compare favourably in terms of number of papers, but do the papers represent important, high-impact discoveries? The index used in this study is the number of papers published in Nature between 1989 and 1998. The advantage of this measure is that it is relatively free from regional bias, and the time delay between discovery and publication is short. The accompanying graph shows the result over the past 10 years for the ING telescopes compared with large telescopes elsewhere that have been in operation for a number of years. The sample includes all telescopes with an aperture larger than 3.5-m, plus the Nordic Optical Telescope, and the INT. (Papers with contributions from more than one telescope are divided equally between those facilities). Clearly the WHT compares very favourably with other telescopes.
Number of publications per year and telescope
WHT INT JKT Total 1984 - 1 - 1 1985 - 10 3 13 1986 - 24 8 32 1987 - 36 16 52 1988 5 52 12 69 1989 15 58 15 88 1990 37 54 26 117 1991 39 63 19 121 1992 42 56 25 123 1993 55 70 30 155 1994 78 63 44 185 1995 90 81 29 200 1996 100 84 52 236 1997 113 77 35 225 1998 118 72 38 228 1999 115 78 46 239 Total 807 879 398 2,084 The charts below show the relative use of data in 1999 ING publications split by instrument used. Also shown is the authorship of all papers from 1984 to 1997 and for 1998-1999 only, split by nationality. The nationality of each author is attributed according to his or her address and equal weight is given to each author. It can be seen that the contribution from the rest of the world (others) has increased significantly as compared to the UK (only) contribution, which encourages us to believe that collaborative programmes are becoming increasingly important.
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