Large and Very Large Telescopes

  • Phil Charles
Part of the Integrated Science & Technology Program book series (ISTP, volume 1)


The last three decades have seen almost exponential growth in the numbers of large and very large telescopes, with the unanticipated current situation that there are almost as many VLTs as there are 4 m-class telescopes. This growth in numbers has been curiosity-driven, but obviously technology-led. After an initial plateau of 4 m telescopes in the 1980s, the cost-scaling with aperture (typically ∼ D2. 7) has required dramatic changes in crucial fundamentals of large telescope design in order to be both technically feasible and politically affordable. However, to meet astronomers’ demands for larger amounts of extremely large telescope time will require exploring new paradigms in large telescope construction. HET/SALT present such an opportunity. Their current status and potential will be described, and used as lessons to be learnt when high technology projects attempt to “break the cost-curve”.


Telescopes Astronomy: surveys Astronomical observatories 



I am grateful to David Buckley and Shireen Davis for assisting in the preparation of some of the figures used here and in providing some of the references.


  1. 1.
    Arecibo Observatory – Puerto Rico,
  2. 2.
    J.M. Beckers, Adaptive optics for astronomy: principles, performance, and applications. Annu. Rev. Astron. Ap. 31, 13–62 (1993)MathSciNetADSCrossRefGoogle Scholar
  3. 3.
    J.A. Booth et al., The Hobby-Eberly telescope completion project. Proc. SPIE 4837, 919–933 (2003)ADSCrossRefGoogle Scholar
  4. 4.
    J.A. Booth et al., The Hobby-Eberly telescope: performance upgrades, status, and plans. Proc. SPIE 5489, 288–299 (2004)ADSCrossRefGoogle Scholar
  5. 5.
    D.A.H. Buckley et al., Commissioning of the Southern African large telescope (SALT) first-generation instruments. Proc. SPIE 7014, 07–15 (2008)Google Scholar
  6. 6.
    P.A. Charles, Science with SALT in the ELT era: a “low-cost” option. in Proceedings “Science with 8–10 m Telescopes in the Era of ELTs and the JWST”, ed. by C. Warden (Fundación Ramón Areces, Madrid, 2010), pp. 124–141Google Scholar
  7. 7.
    Digital Sky Survey,
  8. 8.
    K. Govender, Socio-economic impact of astronomy in South Africa. in “Communicating Astronomy with the Public” Proceedings from the IAU/National Observatory of Athens/ESA/ESO Conference. ed. by L.L. Christensen, M. Zoulias, I. Robson (Eugenides Foundation, Athens, 2008), pp. 160–164Google Scholar
  9. 9.
    G.J. Hill, P.J. MacQueen, L.W. Ramsey, M.D. Shetrone, Performance of the Hobby-Eberly telescope and facility instruments. Proc. SPIE 5492, 94–107 (2004)ADSCrossRefGoogle Scholar
  10. 10.
    G.J. Hill et al., The Hobby-Eberly telescope dark energy experiment (HETDEX): description and early pilot survey results. in Panoramic Views of Galaxy Formation and Evolution, ASP Conference Series, vol. 399, ed. by T. Kodama, T. Yamada, K. Aoki (AstrThe Palomar Transient Factoryonomical Society of the Pacific, San Francisco, 2008), p. 115Google Scholar
  11. 11.
    International Virtual Observatory Alliance,
  12. 12.
  13. 13.
    Large Sky Area Multi-Object Fiber Spectroscopic Telescope, website/en/
  14. 14.
    A.B. Meinel, Cost scaling laws applicable to very large optical telescopes. Proc. SPIE 172(2), 2–7 (1979)ADSGoogle Scholar
  15. 15.
    J. Menzies, H. Gajjar, S. Buous, D. Buckley, P. Gillingham, SALT segmented primary mirror: laboratory test results for FOGALE inductive edge sensors. Proc. SPIE 7739, 27–31 (2010)ADSGoogle Scholar
  16. 16.
    C.M. Mountain, F.C. Gillett, The revolution in telescope aperture, Nature 385, A23 (1998)ADSGoogle Scholar
  17. 17.
    J. Nelson, TMT: the next generation of segmented mirror telescopes. in Proceedings “Science with 8–10 m Telescopes in the Era of ELTs and the JWST”. ed. by C. Warden (Fundación Ramón Areces, Madrid, 2010), pp. 52–63Google Scholar
  18. 18.
    National Astrophysics and Space Science Programme,
  19. 19.
    D. O’Donoghue, Correction of spherical aberration in the Southern African large telescope (SALT). Proc. SPIE 4003, 363–372 (2000)ADSCrossRefGoogle Scholar
  20. 20.
    D. O’Donoghue et al., Saving SALT: repairs to the spherical aberration corrector of the Southern African large telescope (SALT). Proc. SPIE 7739, 21 (2010)Google Scholar
  21. 21.
    Palomar Transient Factory,
  22. 22.
    Panoramic Survey Telescope & Rapid Response System,
  23. 23.
    Properties of the Nordic Optical Telescope,
  24. 24.
    R. Racine, The historical growth of telescope aperture. Publ. Astron. Soc. Pac. 116, 77–83 (2004)ADSCrossRefGoogle Scholar
  25. 25.
    L.W. Ramsey, D.W. Weedman, The penn state spectroscopic survey telescope. in Very Large Telescopes, Their Instrumentation and Programs; (A85-36926 17-89). ESO Proc., Garching, 1984, pp. 851–860Google Scholar
  26. 26.
    L.W. Ramsey, T.A. Sebring, C.A. Sneden, Spectroscopic survey telescope project. Proc. SPIE 2199, 31–40 (1994)ADSGoogle Scholar
  27. 27.
    T.A. Sebring, F.N. Bash, F.B. Ray, L.W. Ramsey, The extremely large telescope: further adventures in feasibility. Proc. SPIE 3352, 792–800 (1998)ADSCrossRefGoogle Scholar
  28. 28.
    Sloan Digital Sky Survey,
  29. 29.
    L. Stepp, L. Daggert, P. Gillet, Estimating the costs of extremely large telescopes. Proc. SPIE 4840, 309–321 (2003)ADSCrossRefGoogle Scholar
  30. 30.
  31. 31.
    Square Kilometre Array, Africa,
  32. 32.
  33. 33.
  34. 34.
    The European Extremely Large Telescope,
  35. 35.
    The Two Micron All Sky Survey at IPAC,
  36. 36.
    J.A. Tyson, New frontiers with LSST: leveraging world facilities. in Proceedings “Science with 8–10 m Telescopes in the Era of ELTs and the JWST”. ed. by C. Warden (Fundación Ramón Areces, Madrid, 2010), pp. 160–177Google Scholar
  37. 37.
  38. 38.
    G.T. van Belle, A.B. Meinel, M.P. Meinel, The scaling relationship between telescope cost and aperture size for very large telescopes. Proc. SPIE 5489, 563–570 (2004)ADSCrossRefGoogle Scholar
  39. 39.
    M.S. Longair, Very large optical-infrared telescopes: today and tomorrow. in Proceedings IAU Symposium 232, ed. by P.A. Whitelock, M. Dennefeld, B. Leibundgut (Cambridge University Press, Cambridge, 2006), pp.13–24Google Scholar
  40. 40.
    P.T. Wallace, The pointing and tracking of the Anglo-Australian 3.9 metre telescope. in Conference on Optical Telescopes of the Future, Geneva, Switzerland, Proceedings. (A79-14001 03-89) (European Southern Observatory, Geneva, 1978), pp. 123–131Google Scholar
  41. 41.
    WFCAM - The UKIRT Wide Field Camera,
  42. 42.
    P.A. Whitelock, Astronomy and Development in Southern Africa. in Proceedings of “Accelerating the Rate of Astronomical Discovery” at the 27th IAU General Assembly, Rio de Janeiro, Brazil. Published online at, id.19 (2009)

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.South African Astronomical ObservatoryCape TownSouth Africa
  2. 2.School of Physics & AstronomyUniversity of SouthamptonSouthamptonUK
  3. 3.Department of AstronomyUniversity of Cape TownCape TownSouth Africa

Personalised recommendations