In words spelled with aught and ought, the letters u & gh are silent, and the vowel is pronounced with the open ɑ/ɔ sound.
(The sounds /ɑ/ and /ɔ/ are pronounced the same in the West Coast variety of American English).
taught = tot
bought = bot
caught = cot
He thought about it all afternoon.
She brought watermelon to the picnic.
Princess Leia fought valiantly.