11. Based upon an annual parallax shift of 7.53 milliarcseconds, the distance to this star is about. 12. By contrast, "'astrometric radial velocity "'is determined by secular change in the annual parallax ). 13. The parsec ( 3.26 light-years ) is defined as the distance for which the annual parallax is 1 arcsecond. 14. Annual parallax is normally measured by observing the position of a star at different times of the year as Earth moves through its orbit.15. Based upon an annual parallax shift of 0.16625 arc seconds as measured by the Hipparcos satellite, this system is from Earth. 16. Based upon an annual parallax shift of 0.184 arc seconds as measured by the Hipparcos satellite, this system is from Earth. 17. Annual parallax is normally measured by observing the position of a star at different times of the year as the Earth moves through its orbit.18. Based upon an annual parallax shift of 10.23 ( with a 3 % margin of error ), the distance to this star is. 19. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.0643, corresponding to a physical distance of about from the Sun. 20. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.031843, which is equivalent to a distance of around from the Sun.
