Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
Hostname: page-component-77c89778f8-n9wrp Total loading time: 0 Render date: 2024-07-21T23:24:58.255Z Has data issue: false hasContentIssue false

4 - Competing Primary Mirror Designs

from Part 1 - Optical Observatories

Published online by Cambridge University Press:  15 December 2016

David Leverington
Get access

Summary

Spun Honeycomb Mirrors

The second half of the twentieth century saw the development of three different designs of primary mirror for large optical reflectors. These were spun honeycomb mirrors as used in the Vatican Advanced Technology Telescope on Mount Graham, segmented mirrors (see Section 4.2) as used in the Keck Telescope on Mauna Kea, and thin meniscus mirrors (see Section 4.3) of the sort used in ESO's New Technology Telescope on La Silla. A fourth type, a liquid mirror (see Section 4.5), was also developed, but this had more limited applications. This present section outlines the development of spun honeycomb mirrors as produced at the University of Arizona's Steward Observatory Mirror Laboratory.

The Multiple Mirror Telescope (MMT) had been completed at the Whipple Observatory on Mount Hopkins, Arizona in 1979 with six 72 inch (1.8 m) honeycomb mirrors. These mirrors, made of low expansion, fused silica glass, had been obtained as Air Force surplus equipment. The design of this MMT (see Chapter 10) was innovative in many ways. For example, the observatory building had been designed to allow rapid air movement across both the mirror and telescope structure, allowing them to achieve ambient temperatures quickly and stay there. The honeycomb structure of the mirrors also assisted this.

Neville Woolf of the University of Arizona suggested to his colleague Roger Angel that he look into the possibility of building a larger telescope than the MMT of the same general design.(1) Angel was impressed by the performance of the MMT's honeycomb mirrors and decided to look into the possibility of building larger ones without using expensive low-expansion glass. Instead, Angel and his graduate student John Hill decided to use borosilicate glass, as not only was it cheaper but it had a much lower melting temperature than the low-expansion alternatives, making it easier to cast.

Honeycomb backing for mirrors had been around for some time. The design, which was then called cellar or ribbed, had first been suggested by George Ritchey in the 1920s,(2) and had been used in a modified form for the 200 inch (5 m) Palomar Telescope that saw first light in the late 1940s.

Type
Chapter
Information
Observatories and Telescopes of Modern Times
Ground-Based Optical and Radio Astronomy Facilities since 1945
 , pp. 67 - 95
Publisher: Cambridge University Press
Print publication year: 2016

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. McCray, W. Patrick, Giant Telescopes: Astronomical Ambition and the Promise of Technology, Harvard University Press, 2004, p. 121.
2. Ritchey, G. W., L'Evolution de l'Astrophotographie et les Grandes Telescopes de l'Avenir, Société Astronomique de France, 1929.
3. Angel, J. R. P., and Hill, J. M., Honeycomb Mirrors of Borosilicate Glass, in Proceedings of the ESO Conference on Scientific Importance of High Angular Resolution at Infrared and Optical Wavelengths, Garching, March 24–27 1981, pp. 61–65.
4. Mammana, Dennis L., The Incredible Spinning Oven, Sky and Telescope, July 1985, pp. 7–9.Google Scholar
5. Roger Angel: The Glass Giant of Arizona, Sky and Telescope, July 1985, pp. 10–11.
6. McCoy, Jan, Angel Builds 'em Bigger, Sky and Telescope, August 1988, pp. 128–129.Google Scholar
7. McCray, W. Patrick, Giant Telescopes: Astronomical Ambition and the Promise of Technology, Harvard University Press, 2004, p. 158.
8. Wilson, R. N., Reflecting Telescope Optics II; Manufacture, Testing, Alignment, Modern Techniques, Springer-Verlag, Corrected Second Printing, 2001, pp. 19–23.
9. Robinson, Leif J., Spinning a Giant Success, Sky and Telescope, July 1992, pp. 26–29 and 31.Google Scholar
10. King, Henry C., The History of the Telescope, Charles Griffin 1955 (Dover reprint 1979), p. 206.
11. McCray, W. Patrick, Giant Telescopes: Astronomical Ambition and the Promise of Technology, Harvard University Press, 2004, pp. 102–104.
12. Parker, Barry, Stairway to the Stars; The Story of the World's Largest Observatory, Perseus Publishing, 1994, pp. 68–83.
13. Nelson, Jerry, The University of California Ten Meter Telescope Project: The Segmented Design Hewitt, pp. 11–22, in Adelaide, , (ed.), Kitt Peak National Observatory Conference, Optical and Infrared Telescopes for the 1990s, Tucson, Arizona, 7–12 January 1980, Proceedings Vol. I, Kitt Peak National Observatory, Tucson, Arizona, May 1980.
14. Smith, Jerry, Keck Profile: Jerry Smith: The Early Years, Cosmic Matters, W. M. Keck Observatory, November 2007.
15. Wilson, R. N., Reflecting Telescope Optics II; Manufacture, Testing, Alignment, Modern Techniques, Springer-Verlag, Corrected Second Printing, 2001, pp. 28–33.
16. Wilson, R. N., Reflecting Telescope Optics II; Manufacture, Testing, Alignment, Modern Techniques, Springer-Verlag, Corrected Second Printing, 2001, pp. 34–37 and p. 181.
17. Ciotti, Paul, Mr Keck's Bequest, Los Angeles Times Magazine, May 24 1987, pp. 17–20.Google Scholar
18. Lorell, Kenneth R., et al., Design and operation of the infrared chopping secondary mirror for the Keck 10-m telescope, Proc. SPIE, 2201, Adaptive Optics in Astronomy, 821, May 31 1994.Google Scholar
19. Krisciunas, Kevin, Science with the Keck Telescope, Sky and Telescope, September 1994, pp. 20–26.Google Scholar
20. Shopbell, Patrick L., et al., Remote Observing on the Keck Telescopes, Astronomical Data Analysis Software and Systems XII, ASP Conference Series, Vol. 295, 2003, Payne, H. E., Jedrzejewski, R. I., and Hook, R. N., (eds.), pp. 170–173.
21. Ramsey, L. W., and Weedman, D. W., The Penn State spectroscopic survey telescope in Very large telescopes, their instrumentation and programs, Proceedings of IAU Colloquium No. 79, Garching, West Germany, April 9–12, 1984, European Southern Observatory, 1984, pp. 851–860.
22. Ramsey, Lawrence W., The Spectroscopic Survey Telescope: Concept and Performance, in Optical Astronomy from the Earth and Moon, ASP Conference Series, Vol. 55, 1994, pp. 35–44.
23. Savage, Richard D., et al., Current Status of the Hobby-Eberly Telescope Wide Field Upgrade and VIRUS, in Stepp, Larry M., and Gilmozzi, Roberto, Ground-based and Airborne Telescopes II, Proc. SPIE, Vol. 7012, August 2008.
24. Zimmerman, Robert, Flawed Giants, Sky and Telescope, January 2015, pp. 60–67.Google Scholar
25. Buckley, David, et al., Africa's Giant Eye; Building the Southern African Large Telescope, SALT Foundation, 2005, p. 21.
26. Charles, P. A., Status of SALT, and Joint Science Projects with the GTC, RevMexAA (Serie de Conferencias), 42, 2013, pp. 96–98.Google Scholar
27. Wilson, R. N., Reflecting Telescope Optics II; Manufacture, Testing, Alignment, Modern Techniques, Springer-Verlag, Corrected Second Printing, 2001, pp. 199–204.
28. Wilson, R. N., The History and Development of the ESO Active Optics System, The Messenger, No. 113, September 2003, p. 5.Google Scholar
29. Wilson, R. N., Reflecting Telescope Optics II; Manufacture, Testing, Alignment, Modern Techniques, Springer-Verlag, Corrected Second Printing, 2001, p. 219.
30. Wilson, R. N., Reflecting Telescope Optics I, Springer-Verlag, Second Edition, 2007, p. 450.
31. Johnson, Harold L., The Design of Low-Cost Photometric Telescopes, Vistas in Astronomy, 10, 1968, pp. 149–158.Google Scholar
32. Forbes, Fred F., A 40-cm Welded-Segment Lightweight Aluminium Alloy Telescope Mirror, Applied Optics, 8, 1969, pp. 1361–1363.Google Scholar
33. Wilson, R. N., Reflecting Telescope Optics II; Manufacture, Testing, Alignment, Modern Techniques, Springer-Verlag, Corrected Second Printing, 2001, p. 232.
34. Mottoni, G. de, An Italian 54-inch Reflector of Unusual Design, Sky and Telescope, May 1972, pp. 296–297.Google Scholar
35. Mischung, K. N., ESO's New Technology Telescope (NTT) metallic primary mirror project, Proceedings of IAU's Colloquium Number 79 on Very large telescopes, their instrumentation and programs, Garching, West Germany, European Southern Observatory, 1984, pp. 57–64.
36. Stanghellini, S., and Michel, A., Performance of the First Two Beryllium Secondary Mirrors of the VLT, ESO Messenger 94, December 1998, pp. 10–11.Google Scholar
37. Gibson, Brad K., Liquid Mirror Telescopes: History, Journal of the Royal Astronomical Society of Canada, 85, No. 4, (1991), 158–171.Google Scholar
38. Hickson, Paul, et al., UBC/LAVAL 2.7 Meter Liquid Mirror Telescope, Astrophysical Journal, 436, L201–L204, 1994.Google Scholar
39. Gamma, Eagle, Liquid Astronomy; The Large Zenith Telescope's Mercury Mirror Provides Critical Insights for Next-Gen Instruments, Sky and Telescope, April 2013, pp. 26–30.Google Scholar
40. Hickson, Paul, Liquid-Mirror Telescopes; An Old Idea for Astronomical Imaging is Undergoing a Technology-Driven Renaissance, American Scientist, 95, No. 3, May–June 2007, p. 216.Google Scholar

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×