Looking at the pericope for this Sunday (Luke 21:25-36), I couldn’t help but wonder if the “signs in the sun, moon, and stars” was a reference to Israel/the Church. I’m thinking primarily of the image of the Lady in Revelation 12:1,
And a great sign appeared in heaven: a woman clothed with the sun, with the moon under her feet, and on her head a crown of twelve stars.
This is an image of Israel, the Old Testament Church, pregnant with the Messiah, whom the Dragon (Satan) immediately tries to destroy after his birth. Don’t know if it has merit, but perhaps someone more educated than me could develop the significance in light of the rest of the pericope.