Fast guiding and small telescopes in the 8-m era
Fast guiding and small telescopes in the 8-m era
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8米时代的快速制导和小型望远镜
DOI：
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发表时间：
1998
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影响因子：
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通讯作者：
C. Jenkins
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文献类型：
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作者：
C. Jenkins
快速引导可以改善望远镜提供的图像。它的实施成本可能相当低，并为较小的望远镜提供了升级途径，这将使它们在 8 米时代更加有用。然而，快速引导系统的详细性能必须取决于许多参数，这使得评估其精确的科学效益变得困难。本文提供了一个用于计算快速引导系统性能的综合数学框架。已经计算了一系列模型，这些模型说明了不同尺寸的望远镜在不同波长范围内的好处。审查了三种绩效衡量标准； FWHM、50% 环绕能量直径以及 0.35 角秒孔径中的能量集中。在有用的天空覆盖水平下，与自然视宁度相比的典型增益在 20% 到 40% 范围内。在其他条件相同的情况下，小型望远镜在快速制导方面的获益不如大型望远镜那么多。这些好处对假设的敏感性也得到了检验，这凸显了需要在相关孔径的正确波长范围内工作。对理想模型的最大扰动可能是由于望远镜风震和外部湍流规模造成的。如果有明显的风震，快速引导将产生比自然视宁预期更大的好处。然而，较短的外部规模（几百米）将失去大部分收益。
Fast guiding may improve the images delivered by telescopes. It may be implemented fairly cheaply and ooers an upgrade path to smaller telescopes, which will make them more useful in the 8-m era. However, the detailed performance of a fast guiding system must depend on many parameters and this makes it diicult to assess its precise scientiic beneets. This paper provides a comprehensive mathematical framework for calculating the performance of fast guiding systems. A range of models have been calculated, which illustrate the beneets for telescopes of various sizes in various wavelength ranges. Three measures of performance have been examined; FWHM, 50% encircled energy diameter, and energy concentration in a 0.35-arcsec aperture. Typical gains over natural seeing are found to be in the 20% to 40% range at useful levels of sky coverage. Other things being equal, small telescopes do not beneet as much as large ones from fast guiding. The sensitivity of these beneets to assumptions has also been examined, and this highlights the need to operate in the correct wavelength range for the aperture in question. The biggest perturbations to ideal models are likely to be due to telescope windshake and the outer scale of turbulence. If there is appreciable windshake, fast guiding will yield bigger beneets than expected from the natural seeing. A short outer scale (a few hundred meters) will however lose most of the gains.