This image shows the hourglass shape of the nights shortening and lengthening from winter to summer and from summer to winter, passing clouds, the Moon passing through the night sky every month (diagonal bands) and the Sun climbing higher in the sky during summer.
https://media.astrodon.social/media_attachments/files/113/770/317/059/357/999/original/0cf0b65a42cf71d6.png