Just got it on chapter 4, using this spot http://puu.sh/gO8sF/14dc389b52.jpg

http://i1138.photobucket.com/albums/n524/TSKNew999/NoAchievement.jpg Just did what you did lylat. No dice. Still not unlocking.

Same issue.

Randomly? got it. I was lower than the area on the previous picture.

essen: Good to hear you were able to get it, but it does seem random, because i just tried not only lower, but every single spot where the stars appear. Achievement still locked.

By lower I mean at the bottom of your picture or perhaps even lower.

If only that helped, essen. Tried to activate the achievement everywhere and it's still locked. It refuses for me.

Ah well. Hopefully developer will see this. :-)

I notified the dev a while back about this on Twitter. He doesn't know what the cause might be. Hopefully there will be an update to fix it though.

I hate this achievement, click between two flying islands at night like an idiot!

Developer, do something please, fix or re-code it to only one exactly place on a map!

Had trouble with this achievement, so I tried a few different things.
Finally managed to get it like this:

• Played fullscreen, English.
  
• Finished Chapter 1, then changed to window with ALT+Enter (and it crashed the game).
  
• Started again, windowed, Japanese this time.
  
• Continued from Chapter 2, flew back and forth collecting puzzle pieces until night.
  
• Sang above the pond at night, it took me up to the islands, sang as soon as I regained control and the achievement unlocked.

What a mess this achievement. ^^

Cos, your method did not work for me as you have described, there is one more thing I have done is for the achievement unlocks.

I allow myself to take your text to add the thing more than I did.

• Played fullscreen, English.
  
• Finished Chapter 1, then changed to window with ALT+Enter (and it crashed the game).
  
• Started again, windowed, Japanese this time.
  
• Continued from Chapter 2, flew back and forth collecting puzzle pieces until night.
  
• When night fell, taking the tree seeds (Chapter 1) and plant the 9 flowers (of achievement "A Bevy of Flowers")
  
• Sang above the pond at night, it took me up to the islands, sang as soon as I regained control and the achievement unlocked.

This is what work for me. Hazard?
Thanks Cos for your method who helped me for this achievement.

I'm asking the dev about this, but I've been trying to unlock it myself and from what I can work out, it may be random for each person. [Please note that this is my OWN opinion and experience]
Rather than creating the stars to fall from the island, try and create a star in the night sky. I managed to do it by flying above the island on the right above the beginning of the bridge.
As I said, I'm asking the dev to confirm this at the moment.

Yea, to Cos and Tomoki, that didn't work. I tried. Same with you, cheru. But i do agree that this is entirely random for each person, so it would be nice if there was a more guarenteed way to unlock the achievement for everyone instead of trying to take a blind guess at everything, which only works for you and a small number of people.

Here's what worked for me:
Progress the game all the way towards the end, where the two are sitting on the edge of the cliff towards the right. Go back to the area under the islands, and try it then. That's what worked for me.