Consumer-level digital single-lens reflex (DSLR) cameras are typically not used in professional astronomy because of the systematic errors present in the data as a result of the strong intra- and interpixel variations associated with each of the three different colors (RGB) of the Bayer color filter array. Nevertheless, because the cost of DSLRs compared with traditional astronomical CCDs is so much lower, they represent a potentially underexplored area of scientific quality astronomical imaging, especially in the area of wide-field transient surveys. We demonstrate an algorithm that can achieve ≈ 1 % level photometry in each of the RGB color channels from a stellar source and discuss the application of this algorithm to a ground-based transiting exoplanet survey. The algorithm primarily takes advantage of the large number of stellar sources available for statistical averaging within a single image, using a “lucky point-spread function” approach to identify sources in the image that exhibit systematic errors consistent with a chosen target from the same image. The selection of the appropriate“lucky” reference stars is accomplished through a comparison of the stellar image morphology as it appears on the Bayer array and the reference stars. These references are linearly combined to form a synthetic comparison star that can be used for differential photometry with the target. One key to the algorithm is that all data are retained at the individual pixel-level until the final differential comparison, which helps to alleviate systematic effects that might otherwise cancel each other out during the flux-summing process. We demonstrate the algorithm on HD 339461, a mV = 8.93 G0-type star on which we achieve single-percent level photometry that approaches the fundamental noise floor possible from a single camera.

中文翻译：

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使用拜耳滤色器阵列进行精确测光的空中演示

消费级数码单反 (DSLR) 相机通常不用于专业天文学，因为与三种不同颜色 (RGB) 中的每一种颜色相关的强烈像素内和像素间变化导致数据中存在系统误差拜耳滤色器阵列。尽管如此，由于与传统天文 CCD 相比，数码单反相机的成本要低得多，因此它们代表了一个潜在的科学质量天文成像领域，特别是在广域瞬态调查领域。我们展示了一种算法，该算法可以在来自恒星源的每个 RGB 颜色通道中实现 ≈ 1 % 水平测光，并讨论该算法在基于地面的凌日系外行星调查中的应用。该算法主要利用可用于单个图像中统计平均的大量恒星源，使用“幸运点扩散函数”方法来识别图像中表现出与同一图像中所选目标一致的系统误差的源. 适当的“幸运”参考星的选择是通过比较拜耳阵列和参考星上出现的恒星图像形态来完成的。这些参考线性组合形成合成比较星，可用于与目标的差示测光。该算法的一个关键是所有数据都保留在单个像素级别，直到最后的差异比较，这有助于减轻在通量求和过程中可能相互抵消的系统效应。我们在 HD 339461（一颗 mV = 8.93 G0 型恒星）上演示了该算法，在该恒星上我们实现了接近单个相机可能的基本噪声层的单百分比水平光度测量。