Why is the geographical marker known as the Tropic of Capricorn named after the constellation?

Answer

The Sun appears to reach its southernmost point in the sky as it passes through the region associated with Capricornus

The Tropic of Capricorn is named after the constellation because, historically, the Sun reached its southernmost point in the sky when it was passing through the celestial region associated with Capricornus.

Why is the geographical marker known as the Tropic of Capricorn named after the constellation?
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