Go to the throne room on the second floor of the castle.
If you mean the ones that the Queen gives you from Astro-Knights they are the planets at which the three knights are at.
You get the coordinates by asking the queen, and they are x73 y83, x15 y15, and x83 y20.
The FIRE PLANET is one of the three planets that the Queen gave you the coordinates to, and it is at X-83 Y-20 (up and to the right from the planet Poptropica).
in the throne room.
The Queen gives you the coordinates for the planets where the three space knights have gone, but for the saucer Excalibur they are too far away. The nearby moon at X-56 Y-52 is noted on the page from Mordred's journal (under his bed).
To enter coordinates on Astro-Knights Island in Poptropica, click on the spaceship's navigation controls in the bottom left corner of the screen. Then, enter the coordinates displayed in the walkthrough or guide using your keyboard. Make sure to input the coordinates accurately to reach the desired location in the game.
You should have the coordinates given to you by the Queen. Once you have your new spaceship, it is at X-83 Y-20, up and to the right from the planet Poptropica.
You go left until you reach the castle and then you go upstairs and talk to the queen. She should give you the coordinates. (they didn't really work for me, so i just looked at the map.)
Well, you should have collected some coordinates from the queen. While your in space, you can follow those coordinates to your destination(s).
The castle is the second area on the island, to the right of the Village.
The queen gives you the list of planets that the knights have gone to. But your fuel supply won't reach them. (You go to the moon at X-56 Y-52. The coordinates are on the missing journal page - see related question)
You can't reach any of the planets listed on the Queen's list. You will have to go to the nearby moon (X-56 Y-52). The coordinates are under Mordred's bed. (see related question)