Once you have beaten all three planets and have all three knights with you, travel to the secret asteroid in the Asteroid Belt (down and left in the solar system). The asteroid is at X-11 Y-84.
You do not get or use a bucket on Astro Knights Island.
There is no treasure chest on Astro Knights Island.
There are no bird eggs in astro knights island.
How do you talk to the girl in the hay loft at astro knights island?
its on the island
On every island you have to be the one to save whatever needs saving. That includes the kingdom in Astro Knights Island.
With Mordred
Astro Knights
it is in the left
Once you have built a new spaceship on Astro Knights Island, it will park on top of the castle whenever you leave the island.
on astro knights island
right after Astro-Knights, the 10th island it's going to take a long time, as Astro-Knights will come out in late spring