第谷星的校准格利兹星等：使用亮星的全天光度校准
Calibrated griz magnitudes of Tycho stars: All-sky photometric calibration using bright stars
摘要：
在任意天体位置经常需要5%精度的光度校准;然而，现有的全天空天文目录没有达到这个精度，并且需要耗时的光度校准程序。用恒星光谱模板拟合了依巴谷B_T和V_T星等以及Tycho-2星表中恒星的2 MASS J、H和K星等。从每个恒星的最佳拟合光谱模板出发，计算了合成的SDSS格里兹星等，并构建了一个全天空亮星（V<12）格里兹星等目录。在SDSS测光望远镜观测上测试这种方法，我发现对于g、r、i和z波段，单个恒星的测光精度通常分别为0.12、0.12、0.10和0.08等（1西格玛）。然而，通过使用约10颗这样的恒星，每个校准场的典型误差（系统+统计）可以分别减少到g，r，i和z波段的0.04，0.03，0.02和0.02等。因此，如果在一台仪器的视场中可以观测到几颗校准星，则可以进行精确的光度校准。
英文摘要：
Photometric calibration to 5% accuracy is frequently needed at arbitrary celestial locations; however, existing all-sky astronomical catalogs do not reach this accuracy and time consuming photometric calibration procedures are required. I fit the Hipparcos B_T and V_T magnitudes along with the 2MASS J, H, and K magnitudes of Tycho-2 catalog-stars with stellar spectral templates. From the best fit spectral template derived for each star, I calculate the synthetic SDSS griz magnitudes and constructed an all-sky catalog of griz magnitudes for bright stars (V<12). Testing this method on SDSS photometric telescope observations, I find that the photometric accuracy for a single star is usually about 0.12, 0.12, 0.10 and 0.08 mag (1 sigma), for the g, r, i, and z-bands, respectively. However, by using ~10 such stars, the typical errors per calibrated field (systematic + statistical) can be reduced to about 0.04, 0.03, 0.02, and 0.02,mag, in the g, r, i, and z-bands, respectively. Therefore, in cases for which several calibration stars can be observed in the field of view of an instrument, accurate photometric calibration is possible.
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