The Design and Construction of Large Optical Telescopes

Bely, Pierre-Yves

doi:10.1007/b97612

Cited by 181 publications

(113 citation statements)

References 16 publications

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“…Due to variations in manufacturing process capability, it is useful to summarize the results as a function of minimum machinable rib thickness. 8 The straight lines in Fig. 8 indicate the limits imposed by these rib thicknesses, with each limit constraining the trade space to the lower left.…”

Section: Optimization Resultsmentioning

confidence: 99%

Minimizing high spatial frequency residual error in active space telescope mirrors

et al. 2009

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The trend in future space telescopes is towards larger apertures, which provide increased sensitivity and improved angular resolution. Lightweight, segmented, rib-stiffened, actively controlled primary mirrors are an enabling technology, permitting large aperture telescopes to meet the mass and volume restrictions imposed by launch vehicles. Such mirrors, however, are limited in the extent to which their discrete surface-parallel electrostrictive actuators can command global prescription changes. Inevitably some amount of high spatial frequency residual error is added to the wavefront due to the discrete nature of the actuators. A parameterized finite element mirror model is used to simulate this phenomenon and determine designs that mitigate high spatial frequency residual errors in the mirror surface figure. Two predominant residual components are considered: dimpling induced by embedded actuators and print-through induced by facesheet polishing. A gradient descent algorithm is combined with the parameterized mirror model to allow rapid trade space navigation and optimization of the mirror design, yielding advanced design heuristics formulated in terms of minimum machinable rib thickness. These relationships produce mirrors that satisfy manufacturing constraints and minimize uncorrectable high spatial frequency error.

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Section: Optimization Resultsmentioning

confidence: 99%

Minimizing high spatial frequency residual error in active space telescope mirrors

et al. 2009

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“…[1] Humphries [2] and Bely [3] have suggested that the cost for each component may scale relative to primary mirror diameter uniquely to derive a polynomial composed of the sum of these various scaling factors such that (2) having cost coefficients A i and diameter D. The composite singular scaling power law relative to primary mirror diameter derived from such an equation may vary depending on the mix of these various terms, but is expected to fall within the range noted above.…”

Section: Introductionmentioning

confidence: 93%

Cost scaling of finely segmented filled aperture large telescope observatories: a TMT study

2008

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Previous studies of the scaling of the costs of ground based optical observatories suggest that total costs scale as the primary mirror diameter to a power between 1.7 and 3.0. It has been suggested that observatory costs may scale as primary mirror diameter squared reflecting the dependence on thinner mirrors in the current generation of observatory design. Upon completing the detailed cost estimate in support of the Preliminary Design for the Thirty Meter Telescope, an in depth study was undertaken to understand the sensitivity of the estimate to mirror diameter and thickness in addition to other leading parameters of TMT such as segmentation, primary focal ratio, and enclosure diameter. Based upon this analysis, and expressing the costs scaled solely to the mirror diameter, our analysis suggests that the TMT design scales effectively as the diameter to the power 1.2. We will describe the assumptions used to guide this study, the methods used to build the cost model, and the general results of the model.

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“…The designers of modern large optical telescopes did never look into exposed design concepts. A recent indication for this is textbook [1], written by a large team of most distinguished optical telescope designers, which has a large chapter on Enclosures, but didn't even think about the exposed alternative. May be this is due to a missing kick by a radio telescope designer, which has built some challenging exposed sub-millimeter telescopes.…”

Section: Introductionmentioning

confidence: 97%

Why not exposed extreme large telescopes?

Kärcher¹,

Süß²

2006

SPIE Proceedings

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In designing and building extreme large optical telescopes of sizes above 10m main aperture diameter, the effort for protecting the telescope against environmental influences gets remarkable large in engineering efforts as well as in costs. Large radio telescopes of similar size are built in "exposed" design, which means, that the protections for the sensitive components are integrated into the telescope itself. Long ranging experience even for sub-millimeter wavelength radio telescopes is available. Why not thinking the unthinkable and design exposed extreme large optical telescopes? The paper describes methods to protect the optics, to protect the structures and mechanics, and to overcome the wind and temperature induced disturbances during operations. It shows also means to integrate large and comfortable rooms for the science instruments with free access during operations into the protected area of the telescope.

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The Design and Construction of Large Optical Telescopes

Cited by 181 publications

References 16 publications

Minimizing high spatial frequency residual error in active space telescope mirrors

Minimizing high spatial frequency residual error in active space telescope mirrors

Cost scaling of finely segmented filled aperture large telescope observatories: a TMT study

Why not exposed extreme large telescopes?

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