NGC 7293: The Helix Nebula
A mere seven hundred light years from Earth, toward the constellation Aquarius, a sun-like star is dying. The dying star's last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. Combining narrow band image data from emission lines of hydrogen atoms in red and oxygen atoms in blue-green hues, it shows tantalizing details of the Helix, including its bright inner region about 3 light-years across. The white dot at the Helix's center is this Planetary Nebula's hot, central star. A simple looking nebula at first glance, the Helix is now understood to have a surprisingly complex geometry.