Check the spelling of the object qualifier and make sure the object is visible in the part of the program in which you are referencing it.

检查对象限定符的拼写，并确保在引用它的程序部分中对象是可见的。

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NASA's George Diller said the station is easily visible from Earth because it is more than "It is a large object, getting bigger all the time."

VOA: standard.2010.04.05

An interesting aspect here is that an object can be visible only to those other objects that receive a stream of data from it.

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Edison bulbs function by making a Tungsten filament very hot, and a hot object glows: radiating energy on a broad spectrum of wavelengths, only a small part of which is visible to the eye.

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