heavenly palace
Refers to a palace in heaven, often in mythological or religious contexts. Not an everyday word.
Legend has it that the gods live in a heavenly palace.
Rare, literary, or poetic use for the sky. In modern Japanese, 空 (そら) is the usual word.
Looking up at the sky, the stars were twinkling.
horoscope; astrological chart
Compound of 天 (てん, 'heaven') and 宮 (きゅう, 'palace'). The reading てんきゅう is a straightforward on'yomi combination.