共查询到20条相似文献,搜索用时 985 毫秒
1.
2.
3.
云南天文台丽江高美古和昆明的大气视宁度研究 总被引:5,自引:1,他引:4
研究云南天文台昆明凤凰山和丽江高美古两地点的大气视宁度。利用云南天文台于1994年建立的3孔较差视宁度监视仪(3孔DIMM),对这两个地点的视宁度对比观测。还利用云南天文台的1米望远镜所得到的视宁度与3孔DIMM所测的视宁度进行对比。1米望远镜和3孔DIMM同时观测了7个晚上,各取得308组数据,它们的视宁度平均分别为0.90〃和0.84〃。还讨论了3孔DIMM采用不同曝光时间对视宁度测量值的影响,从实验得出3孔DIMM采用20ms曝光比采用8ms曝光所测视宁度的值要好15%左右。从1995年5月-1996年12月,对丽江高美古和昆明凤凰山二地进行了视宁度的对比观测。在高美古和昆明分别观测了234夜和256夜,观测结果是两个点的视宁度平均;丽江为0.70〃,昆明为0.95〃,同时也统计了两个点的月平均视宁度和最好夜的视宁度,并讨论了两地视宁度随时间的变化规律。 相似文献
4.
5.
差分像运动视宁度测量实验 总被引:1,自引:0,他引:1
本文首先阐明了Fried参数(大气相干长度)r0的物理含义及为什么选取r0作为表征大气视宁度的参数;然后介绍了一种优良的测量r0的方法-差分像运动法,总结了该方法的六个特点,最后给出了在云南天文台用该方法的六个特点,最后给出了在云南天文台用该方法两次实测大气视宁度的实验结果及实验参数,并对结果进行了分析。 相似文献
6.
7.
8.
9.
白日视宁度监测仪和在抚仙湖的初步观测结果 总被引:1,自引:1,他引:0
报导了用南方基地云南天文台太阳差分像运动视宁度监测仪和美国国立太阳天文台的太阳闪烁仪,在云南省澄江县抚仙湖老鹰地红外太阳塔选址点进行的对比观测,简要地介绍了这两种视宁度测量方法的原理,对观测的初步结果进行了分析。 相似文献
10.
从天文选址的角度出发 ,介绍了影响望远镜光学成像质量的大气湍流的成因、特性以及它对星光波前的影响 ,进而对衡量大气宁静度的量度值———大气视宁度做了详细的叙述 ,包括其测量方法 ,以及目前国际天文选址界常用的较差像运动测量仪的测量原理 ,介绍了云台三孔较差像运动测量仪的光学和硬件结构组成部分 ,对图像处理 /采集软件中用Waldie法计算大气视宁度值与用Roddier法计算大气视宁度值的不同之处进行了理论的分析 ,编写了Roddier法相应软件 ,并用于实测中测量了大气视宁度的值 ,得到一些有意义的结果。 相似文献
11.
Instrumentation built to record seeing data automatically via image motion measurements of bright stars in small telescopes is described. The centroid of the star image is found 256 times s-1 in one dimension and is analyzed on-line. The device works over a range of FWHM values as would be seen through a large telescope between <0.1 and 3.0 arcsec. The first results for two identical instruments set up at two locations near the duPont Telescope at Las Campanas Observatory are reported. For a total of 61 nights of data (450 h at each site), the median seeing is 0.6 arcsec, with quartiles at 0.4 and 0.8 arcsec. These are FWHM values referred to 5000 Å at the zenith. So far, the two sites are indistinguishable on average. 相似文献
12.
13.
Shin Oya Hiroshi Terada Yutaka Hayano Makoto Watanabe Masayuki Hattori Yosuke Minowa 《Experimental Astronomy》2016,42(1):85-98
Stellar images have been obtained under natural seeing at visible and near-infrared wavelengths simultaneously through the Subaru Telescope at Mauna Kea. The image quality is evaluated by the full-width at the half-maximum (FWHM) of the stellar images. The observed ratio of FWHM in the V-band to the K-band is 1.54 ± 0.17 on average. The ratio shows tendency to decrease toward bad seeing as expected from the outer scale influence, though the number of the samples is still limited. The ratio is important for simulations to evaluate the performance of a ground-layer adaptive optics system at near-infrared wavelengths based on optical seeing statistics. The observed optical seeing is also compared with outside seeing to estimate the dome seeing of the Subaru Telescope. 相似文献
14.
15.
Restricted by the observational condition and the hardware, adaptive optics can only make a partial correction of the optical images blurred by atmospheric turbulence. A postprocessing method based on frame selection and multi-frame blind deconvolution is proposed for the restoration of high-resolution adaptive optics images. By frame selection we mean we first make a selection of the degraded (blurred) images for participation in the iterative blind deconvolution calculation, with no need of any a priori knowledge, and with only a positivity constraint. This method has been applied to the restoration of some stellar images observed by the 61-element adaptive optics system installed on the Yunnan Observatory 1.2m telescope. The experimental results indicate that this method can effectively compensate for the residual errors of the adaptive optics system on the image, and the restored image can reach the diffraction-limited quality. 相似文献
16.
17.
王海民 《中国天文和天体物理学报》1994,(3)
1991年7月11日日食期间,在大熊湖天文台进行了白光观测.图象是用65cm反射系统和OSL的CCD获得的.月亮边缘始终包含在视场之中,从模糊的月亮边缘轮廓推得了一维的视宁度点扩散函数(PSF),其中包含了望远镜引起的畸变。当天的PSF的宽度介于0.8到1.3弧秒之间。假设存在圆柱对称性,则可得到二维的PSF。然后,运用视宁度函数,对所观测的白光像消卷积。复原方法将观测到的rms反衬值由5%增强到18%;亮桥可能亮于正常的光球强度;暗的半影纤维可能暗到正常光球的50%;而亮纤维可能达到正常光球值。 相似文献
18.
R. W. Wilson N. O'Mahony C. Packham M. Azzaro 《Monthly notices of the Royal Astronomical Society》1999,309(2):379-387
We present results from a study of the seeing quality at the 4.2-m William Herschel telescope at La Palma. The median intrinsic seeing at the site is found to be excellent, and is comparable to that at the Paranal and Mauna Kea observatories. Contributions to the seeing from turbulence within the telescope dome are insignificant. Furthermore, the optical quality and tracking stability of the telescope are good, so that long-exposure image widths close to the limit imposed by the site seeing can be expected. 相似文献
19.
用1.2m地平式望远镜加装的视频CCD、计算机图象数据采集卡及其运用数据处理软件,对2000年4月17日观测视角速度比较快的激光卫星Topex进行了实测及结果分析.每组资料数据为10帧图象,在当天晚上的跟踪观测过程中取得32组数据,用一个二次多项式进行拟合处理后的结果,再把计时误差引起的定位误差分离出来,余下为1.4″误差视为望远镜的跟踪定位精度.为了提高跟踪定位精度,我们认为主要解决CCD计时误差即可. 相似文献