Hey, sure, there is a way to check it!
After completing the whole quest you are getting this item: .
After clicking on it, it shows you the current location of the teleport so if you are planning on doing the bosses, just keep it in your backpack.
The teleport changes every 2 hours and it's random.
Note that only one of these places will be open at a time, and the location is randomly selected every 2 hours (starting after server save). A Spying Eye can be used to find out where the vortex is.