Question: who discovered the first known instance of proper motion
[{'answer': 'Edmund Halley', 'provenance': [{'wikipedia_id': '52015', 'title': 'Proper motion', 'start_paragraph_id': 26, 'start_character': 125, 'end_paragraph_id': 26, 'end_character': 138, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '52015', 'title': 'Proper motion', 'start_paragraph_id': 26, 'start_character': 0, 'end_paragraph_id': 26, 'end_character': 313, 'bleu_score': 0.9603762111511761, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 130906242962652925}, 'section': 'Section::::History.\n'}]}]