There isn't anything left to do here. Where should I go next?

First, make sure that you've found all four elements in the temple.

Once you do that, you'll be given a gift by the alchemists.

It's a bright ball.

Have you seen any places that could use such a ball?

One that looks like a sun?

Go to the model of the solar system in the dome behind the altar, and you
should notice that it's missing a sun.

The left-hand set of controls allow you to put the sun into the model.

Move the lever to the middle position and you can then put the sun in the
basket.

Then move the lever to the top position to raise the basket.  The sun is now
in place.

All you need to do is rotate the planets.

Each of the four elements (and alchemists) has a corresponding planet.