Grote Reber Conducted the First Radio Survey of the Sky

question 96

Multiple Choice

Grote Reber conducted the first radio survey of the sky in the 1930s and 1940s with his 9-m-diameter radio telescope.Why did his telescope need to be so large?

• A) He needed a large light-collecting area because radio sources are notoriously dim.
• B) He needed better angular resolution to identify sources because radio waves are so long.
• C) He needed a higher magnification to identify sources because radio sources are quite small.
• D) He needed a longer focal length because radio sources are so far away.
• E) He needed a shorter focal length because radio sources are so far away.

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