Would it be easier to measure a stars parallax from Pluto? Why?

1 Answer
Jan 26, 2017

It would be easier to measure stellar parallax from Pluto but it would take longer.


The measurement of the distances to stars makes use of parallax and triangulation. The position of a star is measured. It is then measured again six months later when the Earth is at the other side of its orbit. Half of the difference in angle is the parallax angle. The inverse of the parallax angle in arc seconds gives the distance to the star in parsecs.

The limitation of using parallax for finding distances is how small an angle can be measured. Modern satellites can measure the distances of stars up to about 10,000 light years away.

Pluto's orbit is almost 40 times larger than that of the Earth. This means that we could measure distances 40 times further away using parallax.

The problem is however, that Pluto has a 248 year orbital period. So, rather than having to wait 6 months between measurements, it would mean waiting 124 years.