Astrometry and Distance Scale Links and Resources

Simulations and activities

There are several excellent Java applets and other simulations that help convey the concepts of parallax and the cosmic distance scale. Several of these are listed here:

  • Distances to Nearby Stars and Their Motions; from the University of Washington contains a useful explanation of parallax and the distance scale. This site also has a Java applet that allows you to observe parallax in a pseudo- 3D manner and explore the effect of altering factors such as the orbital baseline. Another activity gives you the chance to measure the parallax of stars and calculate their distances.
  • Stellar Parallax is an effective java applet that shows how parallax occurs. Part of an extensive site for a course, Astronomy 101/103; The Nature of the Universe by Professor Herter, Cornell University.
  • Parallax Activity is part of a much larger Teacher's Guide to the Universe, prepared for the WMAP cosmology mission. This site has several pages on parallax including some activities that can be done in the classroom to demonstrate the principles of parallax.
  • Astrometry is an excellent interactive site on the history and future of astrometry from ESA, the European Space Agency. It has a number of interactive pages and discusses missions such as Hipparcos and GAIA in addition to being an excellent primer on astrometry.
  • Atlas of Nearby Stars is a Java-based site written by Brian R. von Konsky that includes a number of virtual activities such as finding the distance to Alpha Centauri by parallax (© Curtin University of Technology). Worth exploring.
  • Cosmic Distance Scales is an interesting NASA site that helps you visualise the relative scale of the Universe through a series of zoom-out pages. Similar to "Powers of Ten" without the scientific notation (NASA/GSFC).
  • Powers of Ten is an interactive java applet that goes from the very large (extragalactic) down to the very small (quarks) through a sequence of images. An excellent way to visualise the scale of objects in the Universe.

Other parallax and distance scale sites

Space missions

  • Hipparcos Homepage for the Hipparcos satellite launched in 1989 and the resultant catalogs. This site also contains a wealth of detail on parallax, astrometric science and the results from the mission.
  • GAIA Homepage for ESA's astrometry mission due for launch in 2010.
  • The Space Interferometry Mission is a NASA astrometry mission due for launch in 2009.