Surveying a Slice of the Universe: The Charge Coupled Device (CCD) Transit Instrument (CTI) Survey

电荷耦合器件(CCD)/传输仪器（CTI）每晚用两种光学颜色测量大约15平方度的天空，直到视觉亮度的极限星等大于21（信号对噪声的信噪比大于5）。每天晚上测量V星等以及紫外线(U)、蓝色(B)、红色(R)或红外线(I)中的一个。选择的颜色将优化相对于天空亮度的信噪比。红外CCD将提供同一条带上大约4平方度的夜间K星等。CTI的观测计划是在同一条天空上停留数年，每年集中观测相同的45平方度数年（红外12平方度），既监测条带中物体的亮度变化，又通过添加多个夜晚的数据获取更深层次的图像。从该仪器获得的数据将用于解决各种天文问题，从发现附近的恒星到测量遥远类星体的变异性。三个科学项目将由项目天文学家处理。这些计划是：1)在变异性和颜色的基础上发现和监测类星体，2)确定超新星的产生率，以及3)发现用作距离指示器的超新星。

The Charge-Coupled Device (CCD)/Transit Instrument (CTI) surveys nightly about 15 square degrees of the sky in two optical colors to a limiting magnitude of visual brightness greater than 21 signal to noise S/N greater than 5). Each night the V magnitude is measured as well as one of Ultraviolet (U), Blue (B), Red (R), or Infrared (I). The colors will be selected to optimize S/N relative to the sky brightness. An infrared CCD will provide nightly K magnitudes for about four square degrees of the same strip. The observing program of CTI is to remain on the same strip of sky for several years, intensively observing the same 45 square degrees per year for several years (12 square degrees in the IR), both to monitor the brightness changes of the objects in the strip and to acquire deeper images by adding data from multiple nights. Data derived from this instrument will be used to address a variety of astronomical problems ranging from discovery of nearby stars to measurement of variability of distant quasars. Three scientific programs will be addressed by project astronomers. These programs are : 1) the discovery and monitoring of quasars on the basis of variability and color, 2) a determination of the supernovae production rate, and 3) discovery of supernovae for use as distance indicators.