The planetarium is in the village. The planets in the telescope are not important except as background to the story.
You do not get or use a bucket on Astro Knights Island.
There is no treasure chest on Astro Knights Island.
You do not have to look through the telescope. It just familiarizes you with the solar system : the three planets (jungle, ice, and fire) and the nearby moon.
There are no bird eggs in astro knights island.
its on the island
How do you talk to the girl in the hay loft at astro knights island?
Nothing. It just shows you a view of the three planets and the Pewter Moon near the planet Poptropica.
On every island you have to be the one to save whatever needs saving. That includes the kingdom in Astro Knights Island.
Once you have built a new spaceship on Astro Knights Island, it will park on top of the castle whenever you leave the island.
You can see the rest of the Poptropica solar system, including the nearby moon. This is only information and nothing you need to solve the game.
on astro knights island
With Mordred