However, once you get beyond a few hundred parsecs, this kind of measurement gets really hard to do, and even with the best telescopes, parallax is only measurable out to about 1000 parsecs.

Measuring this parallax allows you to directly determine the distance to these stars, and the "nearest" ones are arbitrarily defined to be within 10 parsecs (32.6 light years), which corresponds ...

The amount of stellar wiggle in the parallax method is measured in angles — degrees, arcminutes, and arcseconds, and these angles can used to define distances.

Parsec is short for “parallax second”, and if you remember your trigonometry, this is the length of the hypotenuse of a right-angle triangle when the angle is 1 arcsecond (1/3,600 degrees) and ...

Determining the tiny parallax angles of even the nearest stars was a fiendishly difficult task that occupied generations of astronomers and took almost 300 years to achieve.