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月掩星[Lunar Occultation] [2005-9-19]
iamet 发表在 ¤〖天文〗
| As the moon occults a source, a Fresnel diffraction pattern is produced. Lunar occultations can be performed in the radio, infrared, optical, and X-ray (in fact, the EXOSAT satellite was launched specifically to do X-ray lunar occultations). Radio occultations achieve resolutions on the order of 1 arcsecond, while stellar angular diameters have been measured down to a few milliarcseconds during optical and IR lunar occultations.
The lunar occultation technique works well when the position of the source is known very well and when the object structure is simple. The diffraction pattern, is of course, wavelength dependent. Furthermore, only sources which lie along the orbital track of the moon may be observed.
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学好数理化，走遍天下都不怕！ | |
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