标题： 基于快照观测的明亮恒星地基亚毫秒级CCD测光 显示英文标题

标题： Ground-Based Submillimagnitude CCD Photometry of Bright Stars Using Snapshot Observations

摘要： 我们展示了使用快照CCD成像对相距较远的明亮恒星进行地基亚毫星等（<10^-3）测光。我们常规达到这种测光精度通过（1）选择相似亮度和光谱类型的附近比较恒星，（2）将望远镜聚焦模糊以允许在一次积分中获取高信号（>10^7电子），（3）指向望远镜使得所有恒星图像落在同一探测器像素上，以及（4）使用没有非线性或异常像素的CCD探测器区域。我们描述了与夏威夷大学毛纳凯亚山2.2米望远镜上的超新星综合场光谱仪（SNIFS）进行的半自动化观测，通过该设备我们在2小时的时间间隔内以5分钟的采样率达到了5.2x10^-4（0.56mmag）的测光精度。在一个实验中，我们监测了八颗恒星，每颗恒星之间相隔几度，并以每颗恒星约17分钟的采样率实现了亚毫星等精度。我们的快照技术适用于在多颗明亮恒星中自动搜索行星凌日。 显示英文摘要

摘要： We demonstrate ground-based submillimagnitude (<10^-3) photometry of widely separated bright stars using snapshot CCD imaging. We routinely achieved this photometric precision by (1) choosing nearby comparison stars of a similar magnitude and spectral type, (2) defocusing the telescope to allow high signal (>10^7 electrons) to be acquired in a single integration, (3) pointing the telescope so that all stellar images fall on the same detector pixels, and (4) using a region of the CCD detector that is free of nonlinear or aberrant pixels. We describe semiautomated observations with the Supernova Integrated Field Spectrograph (SNIFS) on the University of Hawaii 2.2m telescope on Mauna Kea, with which we achieved photometric precision as good as 5.2x10^-4 (0.56mmag) with a 5 minute cadence over a 2hr interval. In one experiment, we monitored eight stars, each separated by several degrees, and achieved submillimagnitude precision with a cadence (per star) of ~17 minutes. Our snapshot technique is suitable for automated searches for planetary transits among multiple bright stars.