Question

6. [3pt]
The best parallaxes obtained with the Hipparcos satellite have an uncertainty of about 0.001 arc-seconds. If you want to measure an accurate and belieavable distance to a star, the parallax needs to be about 7 times larger than this uncertainty. What is the farthest distance a star can be to have an accurate distance from Hipparcos? Answer in parsecs.

7. [3pt]
The disk of our Galaxy is 100,000 light-years in diameter. What fraciton of the diameter of the Galaxy's disk is the distance for which we can measure accurate parallaxes?

  

8. [3pt]
The Gaia satellite will have greatly improved precision over Hipparcos. The average uncertainty for most Gaia parallaxes will be about 50 micro-arc-seconds, or 0.00005 ar-seconds. How many times farther away will Gaia be able to measure distances to relative to Hipparcos?

Answer 1