The point spread function in Lucky Imaging and variations in seeing on short timescales

被引：31

作者：

Baldwin, J. E. ^{[1
]}

Warner, P. J. ^{[1
]}

Mackay, C. D. ^{[2
]}

机构：

[1] Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England

[2] Inst Astron, Cambridge CB3 0HE, England

来源：

ASTRONOMY & ASTROPHYSICS | 2008年 / 480卷 / 02期

基金：

英国科学技术设施理事会;

关键词：

atmospheric effects; techniques : high angular resolution;

D O I：

10.1051/0004-6361:20079214

中图分类号：

P1 [天文学];

学科分类号：

0704 [天文学];

摘要：

Aims. We investigate the properties of astronomical images made by combining the best images selected from a sequence of short-exposure frames (Lucky Imaging); we assess the match between modelling and observation and discover what variations in seeing occur on very short timescales. Methods. Numerical simulations of a random phase-changing screen passing across a telescope aperture with ideal optics are used to determine the expected point spread function and isoplanatic properties for a range of seeing conditions for comparison with observations. Results. All the model images comprise a diffraction-limited core with Strehl ratios from 0.05-0.5 and an underlying broad disk. The isoplanatic patch sizes are large and coherence times long. The observations are a close match to the models in most respects. Large variations in seeing occur on temporal scales as short as 0.2 s and spatial scales as small as 1 m.

引用

页码：589 / 597

页数：9

共 11 条

[1]

Diffraction-limited 800 nm imaging with the 2.56 m Nordic Optical Telescope [J].