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Instruments on large optical telescopes -- A case study

Kulkarni, S. R. (2016) Instruments on large optical telescopes -- A case study. . (Submitted)

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In the distant past, telescopes were known, first and foremost, for the sizes of their apertures. However, the astronomical output of a telescope is determined by both the size of the aperture as well as the capabilities of the attached instruments. Advances in technology (not merely those related to astronomical detectors) are now enabling astronomers to build extremely powerful instruments to the extent that instruments have now achieved importance comparable or even exceeding the usual importance accorded to the apertures of the telescopes. However, the cost of successive generations of instruments has risen at a rate noticeably above that of the rate of inflation. Indeed, the cost of instruments, when spread over their prime lifetime, can be a significant expense for observatories. Here, given the vast sums of money now being expended on optical telescopes and their instrumentation, I argue that astronomers must undertake "cost-benefit" analysis for future planning. I use the scientific output of the first two decades of the W. M. Keck Observatory as a laboratory for this purpose. I find, in the absence of upgrades, that the time to reach peak paper production for an instrument is about six years. The prime lifetime of instruments (sans upgrades), as measured by citations returns, is about a decade. Well thought out and timely upgrades increase and sometimes even double the useful lifetime. Thus, upgrades are highly cost effective. I investigate how well instrument builders are rewarded (via citations by users of their instruments). I find acknowledgements ranging from almost 100% to as low as 60%. Next, given the increasing cost of operating optical telescopes, the management of existing observatories continue to seek new partnerships. This naturally raises the question "What is the cost of a single night of telescope time". I provide a rational basis to compute this quantity. I then end the paper with some thoughts on the future of large ground-based optical telescopes, bearing in mind the explosion of synoptic precision photometric, astrometric and imaging surveys across the electromagnetic spectrum, the increasing cost of instrumentation and the rise of mega instruments.

Item Type:Report or Paper (Discussion Paper)
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Kulkarni, S. R.0000-0001-5390-8563
Additional Information:Submitted on 21 Jun 2016 (v1), last revised 28 Jun 2016 (this version, v2) Dated: June 29, 2016. I am grateful to the Peggi Kamisato (WMKO Librarian) for providing the Keck bibliography in a machine readable format, to Barbara Schaefer (WMKO Scheduler) for patiently clarifying my queries, to Hien Tran (WMKO Support Astronomer) for direct contribution to x9, to Don Hall (IfA, UH) for providing the material in Appendix A, to Dan Werthimer (UCB) for discussions of the CASPER vision and program and to Dr. Marten van Kerkwijk (U. Toronto) for help with programming to query ADS. I would like thank the scientists who led the projects for providing estimates of cost and other details of their projects: K. Matthews (NIRC, NIRC2), J. Cohen (LRIS, LRIS-B), R. Campbell (LWS), I. McLean (NIRSPEC), X. Prochaska (ESI), M. Bolte (ESI, ADC), S. Faber (DEIMOS), J. Larkin (OSIRIS), P. Wizinowich (AO), S. Adkins (MOSFIRE), S. Vogt (HIRES), C. Rockosi (LRIS-R) and G. Chanan (Phasing and quality of images). I acknowledge useful discussions with the following: A. Barth, R. Campbell, G. Doppmann, D. Elmegreen, E. Kirby, A. Kinney, H. Lewis, J. Lyke and V. Trimble. I am grateful to H. A. Abt, D. A. Frail, & R. Goodrich, A. Ho, A. Mahabal, C. Max, H. Vedantham, M. Strauss & P. Wizinowich for their careful reading. Their suggested corrections and/or constructive criticisms greatly improved the paper. I am grateful to Wendy Freedman of the Carnegie observatories for hosting my mini-sabbatical in the summer of 2013. It was during this time that I took the occasion to convert my preliminary informal analysis into a paper. The serene surroundings combined with an elegant library steeped in astronomical history minimized the pain of tedious investigations, coding and collation of bibliographic references. As usual, I very much appreciate the excellent work undertaken by librarians at various centers and Universities who maintain the ADS data base. The ADS is now a corner stone of astronomical research world wide. In particular, without ADS this paper would not have been possible.
Record Number:CaltechAUTHORS:20161128-102426397
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:72305
Deposited By: Ruth Sustaita
Deposited On:28 Nov 2016 18:54
Last Modified:03 Oct 2019 16:16

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