NGC1805
This large emission nebula, IC 1805, looks like a human heart. Although only the right part of the
nebula is shown in my grayscale H-alpha image shown below, the color image from Astronomy Picture of
the Day shows why it got its name. The nebula glows brightly in red light which is emitted by its most
prominent element: hydrogen. The red glow is created by radiation from a small group of stars near the
nebula's center, an area about 30 light years across. Some of these stars are thought to be 50 times
the mass of our Sun. The radiation from these stars is absorbed by the hydrogen atoms in the "clouds"
of gas and dust in the nebula and then re-emitted as red light. One of the main emission wavelengths
of hydrogen is 656nm, the so-called hydrogen-alpha line. My image was taken with a filter which only
allows this wavelength (actually a 6nm band of light around this wavelength) of light to reach the
camera. The Heart Nebula is located about 7,500 light years away toward the constellation of
Cassiopeia.
nebula is shown in my grayscale H-alpha image shown below, the color image from Astronomy Picture of
the Day shows why it got its name. The nebula glows brightly in red light which is emitted by its most
prominent element: hydrogen. The red glow is created by radiation from a small group of stars near the
nebula's center, an area about 30 light years across. Some of these stars are thought to be 50 times
the mass of our Sun. The radiation from these stars is absorbed by the hydrogen atoms in the "clouds"
of gas and dust in the nebula and then re-emitted as red light. One of the main emission wavelengths
of hydrogen is 656nm, the so-called hydrogen-alpha line. My image was taken with a filter which only
allows this wavelength (actually a 6nm band of light around this wavelength) of light to reach the
camera. The Heart Nebula is located about 7,500 light years away toward the constellation of
Cassiopeia.
| The Heart Nebula from APOD http://apod.nasa.gov/apod/ap061003.html |
| H-alpha image from 10 x 5 minute exposures; TAK 106ED f/5 scope; ST10XME camera; external guiding Borg 77ED |