CC Ādi 13.20

phālguna-pūrṇimā-sandhyāya prabhura janmodaya
sei-kāle daiva-yoge candra-grahaṇa haya
Synonyms: 
phālguna-pūrṇimā — of the full moon of the month of Phālguna; sandhyāya — in the evening; prabhura — of Lord Śrī Caitanya Mahāprabhu; janma-udaya — at the time of His birth; sei-kāle — at that moment; daiva-yoge — accidentally; candra-grahaṇa — lunar eclipse; haya — takes place.
Translation: 
On the full-moon evening of the month of Phālguna when the Lord took birth, coincidentally there was also a lunar eclipse.