Astronomers frequently:

• Sit for long periods of time.

It is important for astronomers to be able to:

• See details of objects that are less than a few feet away.
• Speak clearly so listeners can understand.
• See details of objects that are more than a few feet away.
• Understand the speech of another person.
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• See differences between colors, shades, and brightness.

It is not as important, but still necessary, for astronomers to be able to:

• Determine the distance between objects.