全天相机在多设备巡天中的应用

天文观测站夜天空星像星等信息和天区分布信息可用于指导多设备巡天观测.建立全天相机监测系统(Monitoring all-sky system)对本地天区夜天空实时监测,获取的监测图像需要有效的方法进行处理以提取全天图像星像信息.由于全天图像视场大和高阶扭曲的影响,采用天顶等距投影与多项式函数组合的方法计算图像的底片常数.天文定位的均方根残差约为0.15个像素.通过对图像中亮星部分测光得到的星等差,改正大气消光误差.最后使用HEALPix (Hierarchical Equal Area isoLatitude Pixelation)方法实现天区划分和每个天区可观测极限星等值的存储.

The Application of All-sky Camera in Multi-device Optical Survey

The magnitude and distribution of night sky stars in the astronomical station can be used to guide multi-device sky surveys. A monitoring all-sky system is widely employed to monitor local sky areas, and some methods are described in this paper to extract stars'' information from all-sky images. Due to the impact of the field of view and high-order distortion of the all-sky images, a combined approach of zenith equidistant projection and polynomial function is applied to astrometry. The root mean square residual of astrometry solution is about 0.15 pixel. By photometry of bright star parts in the image, we can use the differential magnitude values to correct atmospheric extinction errors. Finally, the HEALPix (Hierarchical Equal Area isoLatitude Pixelation) partition represents the sky area of optical surveys and limiting magnitude.