NASA's Mission to Pluto and the Kuiper Belt
For nearly two centuries, astronomers have used the parallax effect – how the apparent position of an object varies when seen along different lines of sight -- to measure the distances of faraway stars.
On April 22 and 23, the New Horizons spacecraft will take images of two of the nearest stars, Proxima Centauri and Wolf 359. When combined with Earth-based images made on the same dates, the result will be a record-setting parallax measurement. Read more about that here.
Amateur astronomers with small telescopes and CCD cameras can take part in this effort by imaging the same stars on the same nights from Earth. Combining their images with those made from New Horizons, it will be possible to create 3D images of nearby stars against their background star fields.
New Horizons' target stars can be observed by anyone with a camera-equipped, 6-inch or larger telescope. Once New Horizons sends its images to Earth, the mission team will provide them for comparison to images obtained with amateur telescopes. Wolf 359 and Proxima Centauri will appear to shift in position between the Earth-based and space-based images.
Combined stereo images will show each star "popping out" from the background star fields. Expect to see all images from New Horizons – from the spacecraft alone and 3D images from the mission team – in May.
Read more about how you can take your own images and participate in this historic outreach activity!
This figure illustrates the phenomenon of stellar parallax. When New Horizons and observers on Earth observe a nearby star at the same time, it appears to be in different places compared to more distant background stars -- this is because New Horizons has traveled so far out in space (nearly 5 billion miles) that it has to look in a different direction to see that star. The small images below Earth and New Horizons show each unique view. Note that the farther-away background stars stay in the same place, but the nearby star appears to move between the two vantage points. (Credit: Pete Marenfeld, NSF's National Optical-Infrared Astronomy Research Laboratory)
This figure, by New Horizons contributing scientist Brian May, shows the parallax as an effect of New Horizons' travels deeper into the Kuiper Belt. Traditionally, parallax is measured as the Earth orbits around the sun. The two lines at left show the lines of sight from Earth to the star on either side of Earth's orbit. This causes a small shift in the position of the nearby star compared to more distant stars. New Horizons is so far away that a much larger shift in the line of sight to the star occurs. (Credit: Brian May)