I thought that "standard candles" were required to estimate the distance to any region of space?
How can the distance to arbitrary stars be determined without these markers?
There is a limit to this method of measurement, based on the accuracy of the telescope. For Gaia:
> The European Space Agency's Gaia mission is expected to measure parallax angles to an accuracy of 10 microarcseconds for all moderately bright stars, thus mapping nearby stars (and potentially planets) up to a distance of tens of thousands of light-years from Earth.
The Milky Way is about 100,000 light-years wide. So it is able to accurately measure the distance for a _lot_ of stars around us in our galaxy.
This video probably explains it better: https://www.youtube.com/watch?v=Jdy09y0A4t0
Maybe science fiction authors can stop making up locations entirely now.