Increasing the Range and Accuracy of Current Bright Object High Precision Astrometry

匹兹堡大学Thaw refrator的多通道天文光度计（MAP）将进行升级，将其星等限制从目前的12级扩展到15级，并将其精度提高两倍，比目前的系统好。精确到几毫弧秒的相对天文测量将可以用于夜间观测。该仪器的独特之处包括：通过扫描星场来调制恒星通量的Ronchi光栅，使用所得信号的相位测量恒星之间的角距离，以及用雪崩光电二极管替换旧的光电倍增管

AST-0138222Gatewood, George D.The Multichannel Astrometric Photometer (MAP) at the Thaw Refractor of the University of Pittsburgh will be upgraded to extend the magnitude limit from its current level of twelve to fifteen and will be upgraded to increase its precision by a factor of two better than the current system. Precise, relative astrometry to a few milliarcseconds for a night's observing will be enabled. Unique aspects of the instrument include: a Ronchi grating scanned across the star field to modulate the stellar flux, angular distances between stars measured using the phase of the resulting signals, and the replacement of the old photomultipliers with avalanche photodiodes.***