We present the results of new calibration tests performed by the NASA Meteoroid Environment Office (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the first point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric flux within the camera band pass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at ∼ 0.20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to ∼ 0.05 - 0.10 mag in both filtered and unfiltered camera observations with no evidence for lingering systematics. These improvements are essential to accurately measuring photometric masses of individual meteors and source mass indexes.

中文翻译：

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改进流星摄像机系统的光度校准

我们展示了 NASA 流星体环境办公室 (MEO) 执行的新校准测试的结果，旨在帮助量化和最小化来自摄像机观测的流星光度测量的系统不确定性。这些系统性不确定性可以分为两个主要来源：对 MEO 的 Watec 902H2 Ultimate 摄像机的线性校正的不完全理解以及由 Watec 摄像机的 Sony EX-View HAD 带通和用于确定的带通之间的转换引起的流星星等的不确定性参考星等。为了解决第一点，我们使用两个独立的实验室测试对八台摄像机进行了测量，测量了 MEO 标准流星摄像机的线性响应。我们凭经验确定的线性校正对于在低相机强度水平下执行准确的光度测量至关重要。关于第二点，我们计算了参考星 EX 带通中的合成星等。这些合成星等能够直接计算相机带通内流星的光度通量，而无需对其光谱能量分布进行任何假设。单个参考星合成星等的系统不确定性估计约为 0.20 mag，并受到参考目录中可用光谱信息的限制。这两项改进允许在过滤和未过滤的相机观测中零点精确到 ~ 0.05 - 0.10 mag，没有挥之不去的系统学证据。