Here are the nighttime, starry, dreamy songs I can think of. Some ballads, some uptempos...

BoA - Amazing Kiss
BoA - Every Heart - Minna no kimochi -
BoA - Milky way
BoA - Nobody But You
BoA - Nothing's gonna change
BoA - Your Color
Jay Chou - Qing Xing
Do As Infinity - Under the Moon
ORANGE RANGE - * ~ Asterisk ~
Morning Musume. - Furusato
Morning Musume. - WHY
Kuraki Mai - Like a Star in the Night
Miura Daichi - No Limit featuring Utamaru (from RHYMESTER)
Otsuka Ai - 5：09a.m
Utada Hikaru - Hikari
Dong Bang Shin Gi - Rising Sun
Hamasaki Ayumi - A Song is born
Hamasaki Ayumi - HANABI
Hamasaki Ayumi - HAPPY ENDING
Hamasaki Ayumi - kanariya
Hamasaki Ayumi - walking proud
Hamasaki Ayumi - Who...
Miyavi - Kimi ni negai wo
Onitsuka Chihiro - Gekkou
Juli - Sterne
Nek - Cielo e Terra
Tiziano Ferro - Sere nere