What technique is being used in this sentence he moon faithful yet blind?

The technique being used in this sentence is an oxymoron. An oxymoron is a figure of speech that juxtaposes two seemingly contradictory terms. In this case, the terms "faithful" and "blind" are opposites. "Faithful" suggests a strong belief or trust, while "blind" suggests a lack of awareness or understanding. By combining these two terms, the author creates a paradoxical statement that emphasizes the complexity of the moon.