The 24 elders lowering themselves before the throne are the divisions of the day and the star-map read across the 24 hours, the whole measured circle of the heavens giving service to the seat of higher consciousness within a person. Their worship is not groveling praise but service, the older words behind it meaning to serve rather than to flatter, so the ordered time-cycle of the self offers itself to its own ruling center. Casting down their crowns is the surrender of every lesser authority, each division laying its rule at the one seat that outlasts them all, the higher mind that lives on without end.
This is the interior clock and star-chart aligning under the awareness that governs it. What looks like a heavenly court is the self's own measured order deferring to its summit. The meaning is clear: every part of a person's inner cycle gives up its separate claim and serves the higher consciousness at the center.
Throne: the seat of higher human consciousness within a person, the enduring ruling center
4 and 20 elders: the 24-hour division of the zodiac star-map, the measured circle of the heavens within the self
Crowns: the separate authorities each inner division holds, laid down before the ruling center