Near-infrared coronagraph imager on the Subaru 8m telescope
Near-infrared coronagraph imager on the Subaru 8m telescope
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Subaru 8m 望远镜上的近红外日冕仪成像仪
DOI：
10.1117/12.460762
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Y. Kamata
中科院分区：
文献类型：
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作者：
K. Murakawa;H. Suto;M. Tamura;H. Takami;N. Takato;S. Hayashi;Y. Doi;N. Kaifu;Y. Hayano;W. Gaessler;Y. Kamata
介绍了一种安装在斯巴鲁8米望远镜上的自适应光学日冕成像仪（CIAO）。与Subaru 36元件自适应光学（AO）相结合，CIAO可以在K波段产生近似0.07 arcsec半高宽的衍射极限图像，并在典型视宁度条件下以1 arcsec间隔产生约10 mag差异的高动态范围成像。自2000年2月首次观测以来，我们进行了无日冕掩模和有日冕掩模的成像性能测试。由于天气条件的限制，在最佳观看条件下的性能尚未测试。在0.4 - 0.8角秒的典型视宁度条件下，使用0.2 - 0.8角秒掩模的PSF的光晕分量比不使用掩模的AO的PSF的光晕分量减少了70%。即使在校正之后，残余波前误差通常具有1.2 rad 2，其对应于K波段处约0.3的Strehl比。这种波前误差会降低成像质量，这是非高阶自适应光学地面望远镜日冕观测中的一个常见问题。然而，我们强调，我们的电晕放电有各种优点：清洁的点扩散函数的CIAO，降低读出噪声，和较少的影响，探测器的记忆问题。与小型望远镜上的日冕仪相比，PSF的形状更清晰，它带来了更高的明亮物体周围源的可探测性。
We introduce a near-infrared camera named coronagraph imager with adaptive optics (CIAO) mounted on the Subaru 8m telescope. Combined with the Subaru 36 elements adaptive optics (AO), CIAO can produce nearly diffraction limited image with approximately 0.07 arcsec FWHM at K band and high dynamic range imaging with approximately 10 mag difference at 1 arcsec separation under typical seeing conditions. We have carried out performance tests of imaging without and with coronagraph mask since its first light observation held on 2000 February. Because of limited weather conditions, the performance under best seeing conditions has not been tested yet. At a typical natural seeing condition of 0.4 - 0.8 arcsec, halo component of PSF using 0.2 - 0.8 arcsec mask can be reduced up to 70% comparing with that without mask using AO. Even after correction, residual wave front error has typically 1.2 rad2 which corresponds to the Strehl ratio of approximately 0.3 at K band. Such wave front errors degrades the image quality; this is a common problem of coronagraph on the ground-based telescope with non high-order AO. Nevertheless we emphasize that there are various advantages on our coronagraph: the clean PSF of CIAO, reduction of readout noise, and less effect of detector memory problem. Compared with coronagraphs on smaller telescopes, the PSF shape is sharper and it brings higher detectability of sources around bright objects.