Calibration of ShadowCam

IF 0.6 Q4 ASTRONOMY & ASTROPHYSICS

Journal of Astronomy and Space Sciences Pub Date : 2023-12-01 DOI:10.5140/jass.2023.40.4.173

D. Humm, M. Kinczyk, S. Brylow, R. Wagner, E. Speyerer, Nick Estes, P. Mahanti, Aaron Kyle Boyd, M. S. Robinson

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引用次数: 0

Abstract

ShadowCam is a high-sensitivity, high-resolution imager provided by NASA for the Danuri (KPLO) lunar mission. ShadowCam calibration shows that it is well suited for its purpose, to image permanently shadowed regions (PSRs) that occur near the lunar poles. It is 205 times as sensitive as the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC). The signal to noise ratio (SNR) is greater than 100 over a large part of the dynamic range, and the top of the dynamic range is high enough to accommodate most brighter PSR pixels. The optical performance is good enough to take full advantage of the 1.7 meter/pixel image scale, and calibrated images have uniform response. We describe some instrument artifacts that are amenable to future corrections, making it possible to improve performance further. Stray light control is very challenging for this mission. In many cases, ShadowCam can image shadowed areas with directly illuminated terrain in or near the field of view (FOV). We include thorough qualitative descriptions of circumstances under which lunar brightness levels far higher than the top of the dynamic range cause detector or stray light artifacts and the size and extent of the artifact signal under those circumstances.

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校准 ShadowCam

ShadowCam 是 NASA 为 Danuri（KPLO）月球任务提供的高灵敏度、高分辨率成像仪。ShadowCam 校准结果表明，它非常适合拍摄月球两极附近的永久阴影区（PSR）。它的灵敏度是月球勘测轨道器照相机（LROC）窄角照相机（NAC）的 205 倍。在很大一部分动态范围内，信噪比（SNR）大于 100，动态范围的顶端足以容纳大多数较亮的 PSR 像素。光学性能良好，可以充分利用 1.7 米/像素的图像比例，校准后的图像具有均匀的响应。我们描述了仪器的一些伪影，这些伪影可以在未来进行修正，从而进一步提高性能。对于这次任务来说，杂散光控制非常具有挑战性。在许多情况下，ShadowCam 可以在视场（FOV）内或附近对有直接照明地形的阴影区域进行成像。我们对月球亮度水平远高于动态范围顶端导致探测器或杂散光伪影的情况，以及在这些情况下伪影信号的大小和范围进行了全面的定性描述。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Astronomy and Space Sciences ASTRONOMY & ASTROPHYSICS-

CiteScore

1.30

自引率

20.00%

发文量

审稿时长

12 weeks

期刊介绍： JASS aims for the promotion of global awareness and understanding of space science and related applications. Unlike other journals that focus either on space science or on space technologies, it intends to bridge the two communities of space science and technologies, by providing opportunities to exchange ideas and viewpoints in a single journal. Topics suitable for publication in JASS include researches in the following fields: space astronomy, solar physics, magnetospheric and ionospheric physics, cosmic ray, space weather, and planetary sciences; space instrumentation, satellite dynamics, geodesy, spacecraft control, and spacecraft navigation. However, the topics covered by JASS are not restricted to those mentioned above as the journal also encourages submission of research results in all other branches related to space science and technologies. Even though JASS was established on the heritage and achievements of the Korean space science community, it is now open to the worldwide community, while maintaining a high standard as a leading international journal. Hence, it solicits papers from the international community with a vision of global collaboration in the fields of space science and technologies.