However, considering that our world's stars and planets are likely different from those of whatever lore dnd exists in for the player. Therefore the names would have to be changed to something relevant to any place.
Yes, I certainly agree and so I have updated the original graph (just so it looks nicer, nothing else). I think that applying some sort of heavenly body to a character would be pretty cool (though you practically do that with the phases).
“It is pitch black. You are likely to be eaten by a grue.”
Phase of the Sun -- There aren't any effects like this anywhere else in 5e (that I could find). The reason is because it adds extra bookkeeping. It's not overpowered or anything, just tedious.
Phase of the Moon -- Easy to multiclass to get heavy armor and shield for ridiculous AC.
Phase of the Stars -- This is overpowered. It's nearly a free casting of Misty Step, a Level 2 spell slot.
Open Air -- The closest this ability gets to any other class is Oath of Vengeance Paladin, and that's level 3, requires a bonus action to activate, can only use 1/short rest, against one enemy, and only for 1 minute. Meanwhile, open air only requires you to be exposed to the sky, which is probably 1/2 your adventuring career.
Cosmic Persistence -- Is redundant with Phase of the Moon
Cosmic Power -- compare to Draconic Bloodline, where you only gain damage to one damage type.
Phase of the Void -- huge radius with no saves, just automatic crowd control.
The hardest part about making new subclasses in 5e is matching similar magnitudes of power to the existing subclasses at each level, while still bringing something fresh to the class. This is especially difficult with the sorcerer, since nothing compares to Wild Magic. Warlocks cannot be used to compare, since they're a short-rest caster. That leaves you with the wizard schools and draconic bloodline.