The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to 3.26 light-years or 206,265 astronomical units (AU), i.e. 30.9 trillion kilometres (19.2 trillion miles).

2018年9月11日 · One parsec is the distance to an object whose parallax angle is one arcsecond. The radius of the Earth’s orbit equals one astronomical unit (AU), so an object that is one parsec distant is...

English: Parsec Definition diagram The apparent motion of a nearby star is a small ellipse in the sky relative to background stars over the period of a year. The viewpoint is defined as the Earth. The angle representing major axis radius of the elliptical path is the parallax angle.

English: Parsec Definition diagram The apparent motion of a nearby star is a small ellipse in the sky relative to background stars over the period of a year. The viewpoint is defined as the Earth. The angle representing major axis radius of the elliptical path is the parallax angle.

Parsec: A parsec (symbol: pc) is a unit of length used to measure large distances to objects outside the Solar System. One parsec is the distance at which one astronomical unit subtends an angle of one arcsecond.[1]

2022年7月29日 · A parsec is a unit of distance that is often used by astronomers as an alternative to the light-year, just as kilometers can be used as an alternative to miles.

Parsec is an abbreviation of parallax arcsecond. What this means is at a distance of one parsec, a nearby star would undergo a one arcsecond (1/3600 ̊) trigonometric parallactic shift relative to very distant stars across a one AU baseline, as shown in the diagram on the next page.

Derivation of the Parsec. The astrononomical parsec is derived from the following triangle: The baseline is the Earth-Sun distance, or 1 AU. The triangle is a right triangle. The apex angle at right is 1 second (1") of arc. This is the definition of the parallax triangle.

A parsec is the distance from the Sun to an astronomical object which has a parallax angle of one arcsecond. (the diagram is not to scale).

2018年3月19日 · Parsec means 'Parallax of one arcsecond', or the distance to a star/object with a parallax of one arcsecon. Using the diagram below, we can work out a parsec. The distance SD is approximately one parsec. tan(∠EDS) = ES SD. SD = ES tan(∠EDS) = 1AU tan(1") For small angles of θ tanθ ≈ θ. 1'' = 1 3600 th of a degree.