The Rationale for the Common Northern Observatory (CNO)

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1 The Rationale for the Common Northern Observatory (CNO) Johannes Andersen Director, Nordic Optical Telescope Ernesto Oliva Director, Telescopio Nazionale Galileo René Rutten Director, Isaac Newton Group of Telescopes Version 2.1. January 20, Executive Summary This paper presents our common vision for the future combined operation and development of the 4.2-m William Herschel Telescope, the 3.6-m Telescopio Nazionale Galileo, the 2.5-m Nordic Optical Telescope, and the 2.5-m Isaac Newton Telescope. All located at the Roque de los Muchachos Observatory on the island of La Palma, Spain, these telescopes will form a scientifically powerful and cost-effective new facility, the Common Northern Observatory, or CNO. The participating astronomical communities will gain access to a wider range of even more powerful instruments on a world-class observing site, in a fully transparent manner. At the same time, the integrated operation and development of the telescopes and their instrumentation will lead to lower overall cost and foster wider scientific and technical collaborations. Resources and telescope access will be equitably shared, and new partners may join, eventually turning the CNO into a truly European research facility. This working document is a first step towards realizing that vision. Background Progress in astrophysics in the twenty-first century will rely on observations at all frequencies of the electromagnetic spectrum, obtained from space and from the ground and covering the entire celestial sphere. European astronomy must remain a front player in this enterprise. Space missions needed to observe the radiation that does not penetrate the atmosphere are already planned and executed essentially in global cooperation, and by nature are thus unimpeded by national borders. On the ground, a similarly comprehensive suite of facilities is required to meet the requirements for optical/ir observations, providing a wide range of spatial and spectral resolutions and covering the full optical/ir and radio regions as well as the entire sky. The radio community is well served by a range of global-scale facilities such as the European VLBI Network or the new global project ALMA. In contrast, European access to competitive groundbased optical/ir facilities is seriously imbalanced: Through ESO, a comprehensive and versatile suite of state-of-the-art instrumentation on telescopes of 2-10 meters diameter in the southern hemisphere is becoming available to most of the European astronomical community. In the north, however, only a heterogeneous set of facilities in the 2-10 m range exists, and only on a national basis such as GranTeCan or the Telescopio Nazionale Galileo (TNG), or in restricted collaborations such as Gemini and the Large Binocular Telescope (with the US), or the Isaac Newton Group (ING), the Nordic Optical Telescope (NOT), or Calar Alto Observatory. Hence there is scope for more effective collaboration at a European level between telescope operators in the North. The OPTICON Trans-National Access Programme has opened access to all competitive European mid-range telescopes to the entire European community, but the scope of the programme is modest and it has no provision for improving the scientific quality and cost-effectiveness of the facilities.

2 Joint operation and development may assist in optimising the scientific return of the overall complement of instruments, but true synergy in operation can only be fully effective for telescopes located at the same site. This is currently not feasible for the northern European 10-m class telescopes, but can be achieved for the group of telescopes comprised by the ING, TNG, and NOT, all located at the Roque de los Muchachos Observatory on La Palma, Canary Islands, Spain. This document outlines the potential for achieving significant gains in scientific capability as well as cost of operation by merging the ING, TNG, and NOT into a single new night-time facility for a broad European astronomical community, 1 with the working name the Common Northern Observatory (CNO). Its advantages for European astronomy are highlighted below. The common vision Mid-range (2-4 m class) telescopes remain competitive in several of the currently most active fields of research. This is underlined by the unrelenting demand for observing time for a wide range of research programmes, and also borne out by the science impact study carried out by Benn and Sánchez (2001, PASP 113, 385). The advent of 10-m class optical/ir telescopes as well as new, powerful space observatories further accentuates the need for state-of-the-art mid-range facilities as essential tools working in concert with these large facilities. For instance, target selection through survey activities, wide-field observations, or sustained fast-response studies of transient sources (gamma-ray bursts, supernovae) would use the very largest telescopes very inefficiently. Moreover, many areas of research inherently do not require very large collecting areas, but are most effectively carried out on dedicated smaller telescopes. Flexible capability and quick response are then the key requirements for their instrumentation, in addition to the usual ones of sensitivity, field, wavelength coverage, spatial and spectral resolution. The scientific needs for mid-size telescopes largely overlap between national communities, providing a strong incentive for collaboration and integration of facilities, exploiting the specific capabilities and strengths of each and avoiding unnecessary competition and expensive duplication. The vision must therefore be to create a facility with the most powerful combination of these capabilities, available in a transparent manner to a broad European astronomical community and operating as a coordinated, cost-effective facility. In view of the pressure for new large investments in astronomical facilities (ALMA, ELT, SKA, ), construction of new general-purpose 2-4-m European telescopes in the foreseeable future is not likely. A new mid-range facility must therefore be based on existing telescopes located at a worldclass site. For night-time astronomy, the ING, TNG, and NOT are the natural choice of basis for a new European northern-hemisphere research infrastructure, the Common Northern Observatory (CNO), comprising two 4-m class (WHT, TNG) and two 2.5-m telescopes (NOT, INT). Implementation: Scientific capabilities The frontier of astrophysics is turning increasingly towards fields that require a versatile battery of the most sophisticated instruments to be scheduled with maximum flexibility. Many projects study transient sources such as gamma-ray bursts, supernovae, cataclysmic variables and X-ray binaries, or fast-moving Solar System object such as planetary satellites, asteroids, and comets. The study of exoplanets is in very rapid development with a broadening range of techniques, and the study of stellar atmospheres is turning towards non-classical areas such as stellar activity and magnetic fields. Scientific breakthroughs in all these areas continue to be made with 2-4-m telescopes. 2 1 The rationale for our vision stands on its own, but we note that very similar thought are being developed in the US see the report on a recent planning meeting at 2

3 In space, each new satellite observatory (INTEGRAL, SWIFT, Spitzer, ) or sky survey (SDSS, VST/VISTA, LSST, ) brings its own surprises and needs for optical observations to be made at short notice, with instrumental needs ranging from wide-field near-uv imaging to high-resolution spectroscopy in the infrared. Responding to these developments requires versatile state-of-the-art instruments and queue scheduling, which allows to execute urgent alerts instantly and/or when atmospheric conditions are perfect. All four CNO telescopes strive towards this goal in various ways, but doing so individually sets strong limits on what can be achieved. By operating them in queue mode as a unit, they can have a much wider range of instruments permanently at the ready, creating a whole which is far more powerful than the sum of the parts. Individually, the CNO telescopes already offer moderately wide-field optical imaging (all four), adaptive-optics assisted high-resolution imaging (WHT and TNG) and integral-field spectroscopy (WHT), moderately wide-field near-ir imaging and low-resolution spectroscopy (WHT, TNG, NOT), optical long-slit and low-to-medium resolution multi-object spectroscopy (WHT, TNG, NOT), and high-resolution optical spectroscopy (TNG, NOT). Implementation of a laser guide star (LGS) facility is under development at the WHT, a high-resolution IR spectrograph is being built for the TNG, and NOT is being equipped with a stable fibre-fed high-resolution spectrograph allowing synoptic observations with other instruments or telescopes. The WHT and NOT also welcome visiting astronomers with innovative, custom-built instruments. The CNO vision is to take these capabilities to a higher level of performance by combining the best features of each telescope into a coherent common facility. Instruments are traditionally planned, built, and operated on a telescope-by-telescope basis. This constraint limits the overall performance ambition, range of facilities available to each community, and freedom in scheduling. It also leads to inefficient utilisation of precious human and financial resources for the construction and operation of instruments with overlapping capabilities. By combining the strengths of the four telescopes and their operating staff, a wider and more powerful range of observing tools can be made available to astronomers in all participating countries, and at an overall lower cost that will be sustainable also in the future. Every participating community stands to gain from such a system. Technical specialisation of each of the CNO telescopes is thus the key to success. Fewer instrument changes are less labour intensive; they also imply improved reliability, further reducing operational cost. Moreover, with fewer instruments, each can be designed to be more powerful within its field, and the use of human and financial resources for development can be optimised. An actual instrumentation plan must be based on a survey of present and future user interests, but the basic principles are clear already. Adaptive optics will be reserved for the largest telescopes for obvious reasons of diffraction limits and cost; adaptive-optics assisted integral-field spectroscopy would also be photon starved at the smaller telescopes. Optical/near-IR imaging and low-resolution spectroscopy should focus on the telescopes with the sharpest images; image quality and detector size and quality are at least as important as telescope aperture here. The SARG spectrograph at the TNG has uniquely high spectral resolution in an efficient standby position and should remain where it is, while a fiber-fed échelle spectrograph could operate at either the INT or NOT. Given the required user input, an optimised CNO instrumentation plan could be drawn up in a short time. This should include a plan for future upgrades so as to maintain scientific competitiveness over a timescale of 5-10 years. Such instrument upgrade projects will be able to draw on the collective experience and resources of all participating communities. A common programme will also enable more cost-effective use of the few technology centres in the community that will also be responsible for equipping the present and future generations of very large telescopes. 3 3

4 The scientific advantages of the proposed CNO model go well beyond the technical facilities of the telescopes. True integration of the telescopes will promote large international projects that are currently beyond the capability of individual communities. Such scientific collaboration would bring communities together based on scientifically inspired ideas, fostering further collaborations and progress. Full integration of the telescopes will also facilitate scientific programmes that require very close coordination (large surveys, satellite follow-up and coordinated observations, targets-ofopportunity), something very difficult to accomplish in the current setup. Implementation: The user s perspective To the user, the advantages of the CNO concept are large and obvious: A more versatile range of high-performance facilities will be available, with more powerful and reliable instrumentation and more flexibility in scheduling. This would be true for all members of the present user communities, but access to the CNO should be broadened to the European community at large, as a natural extension of the present OPTICON access programme and with EC financial support under a new (and probably larger) OPTICON contract under EU Framework Programme 7. For the individual scientist, this development would translate into an improvement in quality of telescope access at the expense of quantity, consistent with past policies at e.g. ESO, La Silla, and elsewhere. To further reap the benefits of synergy, users will access the CNO facilities through a common proposal mechanism, with a unified proposal form and deadlines, pre-application information channels, peer review process and post-award processing of proposals, and logistic procedures for observing travel and accommodation, etc. Having observing travel funded from the common budget would be attractive, but will depend on funding; service and queue-scheduled observing will no doubt account for a significant part of the observing time in any case, if adequate staff resources can be provided. Likewise, a common approach to archiving of data would yield efficiency savings and overall better service, again provided that the overall funding envelope allows so. Implementation: Organisation The vision at the heart of CNO is a single, coherent and self-sufficient operational unit, based on La Palma and with a broad European user base. The formal organisational basis for the CNO remains to be defined, but sufficient examples exist that identifying a suitable structure is not in doubt. Present partners would retain their identity to the extent they contribute to the budget, and new partners would be able to join in a flexible manner. In this model the EU could play a major role in providing access to European astronomers who do not have access to ESO and/or to other northern facilities, to an extent determined by such financial contributions as the EC would make. In such a system, the financial contributions of each partner would continue to define the fraction of telescope time available to that user community. Undoubtedly, the 20% share of observing time currently reserved for Spain would also be a subject of negotiation The CNO would have a single, multi-national operations staff providing scientific, technical, and logistic support to all users, regardless of their nationality and the origin of the facility they would be using. The unified proposal submission, review, and scheduling and execution procedures would also help to ensure consistent performance standards across the board. High-level managerial control would be through a CNO Council with representation of each of the partners. The Council would approve budgets and plans for the operation and development of the entire facility. A single Director would be responsible to the Council for implementing these plans. 4 4

5 5 Implementation: Finances At the time the CNO is fully implemented, the telescopes will be years old. As telescopes are basically just light collectors feeding instrumentation that evolves much faster than telescope technology, this is no drawback in itself. However, it does mean that the main financial concern in developing forward planning is no longer the initial investment made in constructing the telescopes, but the cost of operating and equipping them in the future. Accordingly, formal issues of ownership become of secondary importance to the financial realities of funding the operations a trend again already in evidence world-wide. The existing facilities ING, NOT and TNG are owned by organizations of different nationality and formal status. In the future, ownership could be transferred to a new body responsible for the CNO, or it could remain as is, with an appropriate body assuming contractual responsibility for operation and maintenance of the facility. In any case, the issue of ownership has legal and contractual implications, also towards the Spanish authorities, that require careful assessment. Given that the major expense component of any observatory operation is manpower, a pooled operation as envisaged for the CNO will bring substantial savings in overall cost. The reduction in labour-intensive and failure-generating instrument changes would be one important factor; the need to maintain fewer different hardware and software instrument standards would be another; and sharing staff reserves to cover compensation for overtime work, vacation, courses and conferences, and other absences would be a third. In a full assessment, the time saved by users in having fewer instruments and proposal preparation systems to deal with should be included, as should the (no doubt more significant) gains achieved by rationalising instrumentation development, although they would not be directly visible in the operational budget of the observatory itself. Any meaningful attempt to assign numbers to these savings will require careful definition of the scientific ambitions for the CNO as regards instrumental capabilities, operational services, and user support, and analysis of the extent to which savings, especially in highly skilled manpower, can be usefully transferred to other activities. But the net amount will be considerable. Implementation: Schedule Merging the present three independent telescope groups into a single, streamlined facility cannot, of course, happen overnight. First, time is needed to develop a consensus that this is the way to go, and this document is the first step towards building such a consensus. Second, the interested partners must be identified and their interests in the benefits and willingness to contribute to the cost of the CNO must be ascertained. Third, a detailed implementation plan must be drafted, negotiated, and approved by the interested partners. From the moment of decision, the speed of implementation will depend on the objectives defined by the partners, including the rate at which the desired streamlining of systems and services must happen. Currently, a time scale of the order of five years to complete the entire process is probably a good guess, assuming that a political decision to go ahead could be taken within the next year or so. Time will tell if this is possible, but specific initiatives are under way by all three groups. Different parts of the process can have different timescales, however. Opening the most competitive facilities to the full community and retiring the least competitive instruments could, in principle, happen soon; thus, the first scientific fruits of the CNO could be reaped quite early. Upgrading the key instrumentation will require more time, dependent on funding and other commitments of the groups involved. Bringing the user interfaces of proposal processing, instrument control, and data handling and archiving to common standards could proceed in parallel. Finally, fusing the three 5

6 staffs into a single group would presumably take the longest time; it is, however, facilitated by the climate of cooperation and friendship already existing among the present staffs. Epilogue At the time of writing, the CNO as sketched above is just a vision shared by the three telescope directors. But the logic of the underlying groundswell in European and global astronomy is compelling; all informal reactions so far have been positive; and the NOTSA Council, the ING Board, and the INAF Director have directed us to pursue the goal vigorously. It is hoped that the CNO concept will be taken under serious consideration by the various potential partners in the very near future and eventually be turned into action to define a plan for the scope and implementation of the CNO in its initial phase. All constructive comments are welcome and will be included in future revisions of this description and in the actions we will undertake. 6 La Palma, January 20, 2005 J. Andersen E. Oliva R. Rutten 6