标题： 使用视宁度受限成像实现亚毫角秒天体测量精度 显示英文标题

标题： Towards sub-milliarcsecond astrometric precision using seeing-limited imaging

摘要： 地球大气湍流会降低地基天体测量的精度。 在这里，我们讨论这些限制，并提出通过适当处理系统误差，并利用韩国微透镜望远镜网络（KMTNet）提供的多个观测时段，视宁度受限的观测可以达到亚毫角秒的精度。 这样的观测可能对通过微透镜探测银河系黑洞至关重要。 我们介绍了使用视宁度受限观测进行精确天体测量的方法和流程。 该方法是Gaia的天体测量全局迭代解法（AGIS）的一种变体，包括几个去趋势步骤。 对KMTNet在典型视宁度为1角秒和像素尺度为0.4角秒的条件下获得的6500张同一区域图像的测试表明，使用来自智利托洛洛山美洲天文台（CTIO）站点的数据，在大约五年的基线上，对于明亮天体（mag <17），相对自行精度可以达到0.1-0.2毫角秒/年。 精度是通过自助模拟估计的，并通过比较两个独立的KMTNet望远镜的结果进一步验证。 显示英文摘要

摘要： The Earth's atmospheric turbulence degrades the precision of ground-based astrometry. Here we discuss these limitations and propose that, with proper treatment of systematics and by leveraging the many epochs available from the Korean Microlensing Telescope Network (KMTNet), seeing-limited observations can reach sub-milliarcsecond precision. Such observations may be instrumental for the detection of Galactic black holes via microlensing. We present our methodology and pipeline for precise astrometric measurements using seeing-limited observations. The method is a variant of Gaia's Astrometric Global Iterative Solution (AGIS) that include several detrending steps. Tests on 6,500 images of the same field, obtained by KMTNet with typical seeing condition of 1 arcsecond and pixel scale of 0.4 arcsecond, suggest that we can achieve, at the bright end (mag <17), relative proper motion precision of 0.1-0.2 mas/yr, over a baseline of approximately five years, using data from the Cerro Tololo Inter-American Observatory (CTIO) site. The precision is estimated using bootstrap simulations and further validated by comparing results from two independent KMTNet telescopes.