HUBBLE REFINES DISTANCE TO THE PLEIADES STAR CLUSTER
The brilliant stars seen in this image are members of a cluster of about 1,000 stars known as the Pleiades, or Seven Sisters. The brightest of the stars are visible to the naked eye on dark nights from Earth and together make a popular target for backyard astronomers.
The color-composite image above was taken by the Palomar 48-inch Schmidt telescope and is part of the Digitized Sky Survey. Now the Hubble Space Telescope's Fine Guidance Sensors have refined the distance to the Pleiades at about 440 light-years, astronomers announced this week.
(The Fine Guidance Sensors are at the periphery of Hubble's field-of-view. The sensors trace a circumference that is approximately the angular size of the Moon on the sky. The observations are overlaid on this related image to give a scale to Hubble's very narrow view on the heavens.)
Hubble Fine Guidance Sensors measured slight changes in the apparent positions of three stars within the cluster when viewed from different sides of Earth's orbit around the Sun. Astronomers took their measurements six months apart over a 2 1/2-year period.
The results were announced Tuesday at a meeting of the American Astronomical
Society in Denver.
Credit: NASA, ESA and
AURA/Caltech
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