Follow this link to skip to the main content

Parallax movie

Parallax Movie

This movie was developed by Professor Rick Pogge at the Ohio State University Astronomy Department.


The top portion of the movie shows what you would see looking at a nearby star over time from Earth. The nearby star, whose distance you are trying to measure, is in red and can be observed to move against the fixed background stars. The bottom portion shows the view of the Earth/Sun/star system from above. The Earth is shown in blue orbiting the Sun (yellow). The line of sight from the Earth to the nearby star, and onto the distant background stars, is shown in red. As the Earth orbits the Sun, the line of sight to the nearby star changes, and the apparent position of the star on the sky (in the top portion of the diagram) can be seen to change as well.

Notice that in the movie two different cases are shown, one after another. In the first, the nearby star is closer to the Earth, while in the latter, it is further away. Observe how the size of the apparent shift changes in each case.

Movie Click here to view the movie
Return Click here to return to finding the distance to HT Cas using parallax

A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC

NASA Logo, National Aeronautics and Space Administration