منابع مشابه
Objective transmission gratings for large schmidt telescopes.
Several lamellar gratings of 18-in. aperture, with 300 diffraction elements per inch, have been made for determining stellar spectra with wide angle telescopes. Central orders are missing at lambda4800, and weak at adjacent wavelengths. The two, equal first orders are about l(m) weaker than spectra by a prism or echelette grating. Dispersion is linear. The procedure of manufacture is adaptable ...
متن کاملBuilding Large Telescopes: Ii- Reflectors
On the turn of the twentieth century the refractor was rapidly approaching its limits in terms of aperture. The main reason for this was the difficulty in manufacturing discs of crown and flint glass with diameters greater than 100 cm. Manufactures of plate-glass could however cast large disks of ordinary crown glass, of lower optical quality, that were suitable for mirrors. It was also known t...
متن کاملOperational Concepts of Large Telescopes *
The singular way of scheduling at major observatories has favored certain types of astronomy. This has led to the discrimination of certain types of observations which could not be accommodated. It is the goal of future operations to open possibilities for some additional types of observational astronomy. Together with improved observatory operations the new observing modes can provide signific...
متن کاملImproving resolution in large telescopes
New discoveries in astronomy require the use of ever larger telescopes. There are two motives for increasing the telescope aperture: greater light-gathering power and the potential for higher spatial resolution. The largest of these telescopes require segmented mirrors, since current technology does not provide for the fabrication of monolithic mirrors with diameters much larger than 8m. In add...
متن کاملWind buffeting of large telescopes.
Unsteady wind loads due to turbulence within the telescope enclosure are one of the largest dynamic disturbances for ground-based optical telescopes. The desire to minimize the response to the wind influences the design of the telescope enclosure, structure, and control systems. There is now significant experience in detailed integrated modeling to predict image jitter due to wind. Based on thi...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1984
ISSN: 0252-9211
DOI: 10.1017/s0252921100106542