AI 中文总结
本文介绍升级后的PICSARR-2偏振仪，表征其在36英寸和14英寸望远镜上的恒星偏振测量性能，精度优异，可用于探索恒星变异性。
AI 中文摘要
本文介绍了升级后的成像CMOS传感器旋转延迟器偏振仪2（PICSARR-2），描述了其应用，并表征了其在36英寸和14英寸望远镜上进行恒星偏振测量的性能。在较大的望远镜上，使用SDSS g'、r'和i'滤光片，以对应12毫秒帧曝光的快速调制速率，对亮恒星记录到的偏振精度σ_p为5.7 ppm；考虑单个观测的内部误差后，极限精度e_p为1.3 ppm。星等m>5的恒星需要更长的帧速率，但对于m>8的恒星，记录的误差仅略高于基于光子散粒噪声的外推值，此时需要更长的帧曝光。观测到的暗弱恒星星等可达m=11。测得的位置角精度为0.0845度，PICSARR-2与HIPPI-2偏振仪的观测结果吻合度很高。在较小的望远镜上，该仪器的性能接近类似水平，且标准恒星观测具有良好的跨平台稳定性。因此，PICSARR-2是探索由多种现象引起的恒星变异性的优秀仪器；本文展示了正在进行的脉动恒星观测活动及其他变星项目的示例。
英文摘要
We describe the upgraded Polarimeter using Imaging CMOS Sensor and Rotating Retarder 2 (PICSARR-2), describe its applications, and characterize its performance for stellar polarimetry on a 36-inch and 14-inch telescope. On the larger telescope in the SDSS $g^\prime$, $r^\prime$ and $i^\prime$ filters a precision of $σ_p=$ 5.7 ppm on bright stars is recorded using a fast modulation rate corresponding to frame exposures of 12 ms; accounting for the internal errors in the individual observations gives a limiting precision of $e_p=$ 1.3 ppm. Longer frame rates are required for stars with $m > 5$, but the recorded errors only underperform a photon shot noise derived extrapolation for $m > 8$, when even longer frame exposures are required. Stars as faint as $m = 11$ were observed. The position angle precision is measured as 0.0845 degrees, and there is very good agreement between observations made by both the PICSARR-2 and HIPPI-2 polarimeters. On the smaller telescope the instrument's performance approaches similar levels, and there is good cross-platform stability in the observation of standard stars. PICSARR-2 is therefore an excellent instrument to explore stellar variability due to a range of phenomena; examples from our ongoing pulsating star campaign and other variable star programs are presented.
Comments27 pages, 19 figures, accepted to JAAVSO
