High Speed Scanner: Digital Access to a Sky-Century

现在，设计和建造一个高速扫描系统是可行的，它可以在30秒内将记录在玻璃板（8 x 10英寸）上的天文图像数字化，达到高光度精度。这使得在玻璃板上数字化保存大量档案数据成为可能，这反过来又使许多类别的天文物体的时间变异性研究能够追溯到整整一个世纪，这是前所未有的。历时最长、覆盖范围最大的一组天文板块，包含在哈佛大学天文台的60万板块中。宇宙“时光机”通过高速网络将一个世纪的恒星数据数字化并提供服务而成为可能，这意味着可以研究天体物理学中的许多关键问题。三个例子包括：造父变星的脉动周期的长期变化，天文距离尺度的宇宙尺度，可以研究，周期变化的测量可以揭示这些明亮恒星内部的核心对流的条件知之甚少；在非常年轻的恒星中，恒星的演化可以在10年到100年的时间尺度上观察到，这些恒星可能会将周围圆盘中的剩余物质转化为行星的诞生；在双星系统中的白矮星、中子星和黑洞中，从双星同伴中吸积物质，可变性是规律而不是例外，因此它们可以通过亮度变化来研究，其结果指向银河系中这些最极端恒星的形成和演化。不仅可以解决已知的现象和问题，而且很有可能发现新的和意想不到的现象。更广泛的影响。这项研究有助于提高公众对宇宙不是静态的认识。进化和变化是规律，而不是例外。对科学教育的影响是巨大的：通过在项目网站上展示“宇宙电影”的片段，从类星体的变化到造父变星的变化，再到附近新形成的恒星和行星系统的变化，学生们可以更好地了解当前天文学的兴奋。对动态宇宙的物理理解甚至比永恒的天空更吸引人。

It is now feasible to design and build a high speed scanner system that can digitize astronomical images recorded on glass plates (8 x 10 in) to high photometric accuracy in under 30 sec. This makes possible the digital preservation of large volumes of archival data on plates which in turn enables time variability studies of many classes of astronomical objects to extend back a full century in time as never before possible. The longest duration set of astronomical plates, and with the largest amount of coverage, are contained in the 600,000 plates of the Harvard College Observatory. The cosmic "time machine" made possible by digitizing and serving a century of stellar data on high speed networks means that a number of key problems in astrophysics can be investigated. Three examples include: Long-term changes in the pulsation periods of Cepheid variable stars, the cosmic yardsticks of the astronomical distance scale, can be studied where period change measurements can reveal the poorly understood conditions of core convection in the interiors of these luminous stars; Stellar evolution can be observed on decade to century timescales in very young stars, which may be converting their left over material in surrounding disks into the birth of planets; In white dwarfs, neutron stars and black holes in binary systems, accreting matter from the binary companion, variability is the rule rather than the exception so they may be studied by the brightness changes, results of which point to the formation and evolution of these most extreme stars in the Galaxy. Not only can known phenomena and problems be addressed, but there is the very likely discovery of new and unexpected phenomena. Broader Impacts. This research is helping to increase public awareness that the universe is not static. Evolution and change are the rule, not the exception. The impact on science education can be large: by showing on the project website segments of the ``cosmic movie" from quasar variations to Cepheid variable pulsation changes to nearby examples of change in newly-forming stars and planet systems, students can better understand the excitement of current astronomy. Physical understanding of the dynamic universe is even more enticing than the immutable sky.