0012g1aa.doc Gran Telescopio CANARIAS TITULO Gran Telescopio CANARIAS Conceptual Design Código : GEN/STMA/0012-R Edición : 1.A Fecha : 22/07/97 Nº de pág. : 199 Instituto de Astrofísica de Canarias C/Vía Láctea, s/n - 38200 La Laguna (Tenerife) - ESPAÑA - Teléfono 34-(9)22-315031 - Fax 34-(9)22-315032 URL: HTTP://www.gtc.iac.es - E-mail [email protected] Juan Carlos González Aceptado por Responsable de Ingeniería de Sistemas Firmado en el original Pedro Alvarez Autorizado por Director de Proyecto Firmado en el original 2 CONTENTS 1. INTRODUCTION...............................................................................................................1 1.1 GRANTECAN, S. A. ..........................................................................................................1 1.2 HISTORICAL BACKGROUND ..................................................................................................1 1.3 REASONS FOR SPAIN TO UNDERTAKE THIS PROJECT .............................................................1 1.4 AN INTERNATIONAL OPPORTUNITY ......................................................................................2 2. REQUIREMENTS..............................................................................................................5 2.1 INTRODUCTION....................................................................................................................5 2.2 SUMMARY OF SCIENCE PROGRAMMES..................................................................................5 2.2.1 Extrasolar planets and faint stellar sources ..................................................................5 2.2.2 Protostellar objects and star formation.........................................................................5 2.2.3 Compact objects and black holes ..................................................................................6 2.2.4 Stellar populations of external galaxies ........................................................................6 2.2.5 Active, starburst and primeval galaxies.........................................................................6 2.2.6 Cosmology....................................................................................................................7 2.3 TOP-LEVEL SCIENCE REQUIREMENTS ...................................................................................8 2.4 DETAILED SCIENCE REQUIREMENTS .....................................................................................8 2.4.1 Theoretical limiting magnitudes....................................................................................8 2.4.2 Telescope diameter .....................................................................................................10 2.4.3 Estimated limiting magnitudes....................................................................................10 2.4.4 Attainable image quality.............................................................................................13 2.4.5 Foci ............................................................................................................................14 2.4.5.1 Cassegrain focus...............................................................................................................................14 2.4.5.2 Nasmyth foci.....................................................................................................................................14 2.4.5.3 Other foci .........................................................................................................................................15 2.4.6 Field of view and image quality ..................................................................................15 2.4.6.1 Visual imaging .................................................................................................................................15 2.4.6.2 Long-slit visible spectroscopy ...........................................................................................................15 2.4.6.3 Multi-fibre spectroscopy ...................................................................................................................15 2.4.6.4 Thermal-IR imaging..........................................................................................................................15 2.4.6.5 AO imaging/spectroscopy..................................................................................................................16 2.4.6.6 Summary of the required FOV ..........................................................................................................16 2.4.7 Adaptive optics ...........................................................................................................16 2.4.8 Background-limited performance................................................................................16 2.4.9 Throughput.................................................................................................................17 2.4.10 Secondary mirror......................................................................................................17 2.4.10.1 Number of secondary mirrors ..........................................................................................................18 2.4.11 Pointing and tracking ...............................................................................................19 2.4.12 Instrumentation.........................................................................................................20 2.4.13 Data reduction and archiving ...................................................................................20 2.4.14 Acquisition and guiding ............................................................................................20 2.4.15 Telescope enclosure ..................................................................................................21 2.4.16 Control system..........................................................................................................21 2.5 OPERATIONAL AND SUPPORT REQUIREMENTS ....................................................................22 3 2.5.1 Operational requirements ...........................................................................................22 2.5.1.1 Modes of operation ...........................................................................................................................22 2.5.1.2 Users of the GTC..............................................................................................................................24 2.5.1.3 Low-level operational guidelines.......................................................................................................25 2.5.1.4 Safety during GTC operation.............................................................................................................25 2.5.1.5 Meteorological limits on telescope operation.....................................................................................26 2.5.2 Support requirements..................................................................................................26 2.5.3 Electromagnetic compatibility requirements ...............................................................27 3. THE GTC SITE................................................................................................................29 3.1 INTRODUCTION..................................................................................................................29 3.2 ROQUE DE LOS MUCHACHOS OBSERVATORY ....................................................................29 3.2.1 Environmental conditions at the ORM ........................................................................30 3.3 SITE OPTIONS.....................................................................................................................31 3.3.1 Site 1 ..........................................................................................................................32 3.3.2 Site 2 ..........................................................................................................................33 3.4 GEOTECHNICAL CAMPAIGN................................................................................................33 3.4.1 Conclusion..................................................................................................................33 3.5 SEEING CAMPAIGN.............................................................................................................33 3.6 METEOROLOGICAL CAMPAIGN ...........................................................................................37 3.6.1 Conclusions................................................................................................................41 3.7 CONDITIONS FOR IR OBSERVATIONS AT THE IAC OBSERVATORIES ....................................41 3.7.1 Model atmospheric transmission for a very good site..................................................42 3.7.2 Constituents of an IR spectrum ...................................................................................43 3.7.3 Wavelength range for making the test .........................................................................43 3.7.4 Observations...............................................................................................................45 3.7.5 Water vapour at the Teide Observatory.......................................................................45 3.7.6 Conclusions................................................................................................................45