It is possible to open Ascendant Chest without drinking from bottle. This chest was in Aphelion's Rest.
Screeshots.
https://cdn.discordapp.com/attachments/536735242581704704/597227511126032424/unknown.png
https://cdn.discordapp.com/attachments/536735242581704704/597227622619021317/unknown.png
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You can open any of them if you manage to stand/hover next to them. You don't need to be Ascendant to open them, just to see the chests and the platforms.