Cosmos : The Shores of the Cosmic Ocean - https://youtu.be/x-bJLG9_sUg?si=1K96fMX2T9iXu0zA&t=783

For the "how far?" https://www.aanda.org/articles/aa/full_html/2011/04/aa16141-...

We can get timing (rather than imaging) parallax...

> We find that with the first method a parallax with an accuracy of 20% or less can be measured up to a maximum distance of 13 kpc, which would include 9000 pulsars. By timing pulsars with the most stable arrival times for the radio emission, parallaxes can be measured for about 3600 ms pulsars up to a distance of 9 kpc with an accuracy of 20%.

(one kpc is 3261 light years)

Not only can they be detected at large distances, but measurements of how far can be done at greater distances than can be done with imaging ( https://www.youtube.com/watch?v=hFMaT9oRbs4&t=608s ).