Meet the Ghost of Jupiter, a planetary nebula in the constellation Hydra which was discovered 227 years ago this month on February 7, 1785 by William Herschel. He cataloged it as H IV.27. A little over 100 years later this became NGC 3242 in J. L. E. Dreyer's New General Catalogue of 1888.
This image was captured from my patio in Pompano Beach, Florida in April of 2006. The boys and I were using an 8in reflecting telescope at F/4 and the Orion Color CCD imaging camera with Maxim Essentials software. A total of 45 images of 15 seconds each were made and the best 30 were incorporated into the final image for a cumulative exposure time of 7.5 minutes. Final processing and labeling was done with Paint Shop Pro.
Viewing the magnitude 9 Ghost of Jupiter is easily accomplished with a small telescope and appears as a small bluish-green orb. Larger telescopes will reveal a central white dwarf star. Finding the Ghost is made easy this month by the position of Mars as a key reference point and drawing an imaginary line south through the 3.8 magnitude Red Giant Mu Hydrae. Just less than 2 degrees past Mu Hydrae and slightly to the east of that line will be the Ghost.
The star chart above shows Mars, Mu Hydrae and the Ghost of Jupiter about an hour and half after rising. The best time to try to view the Ghost would be when it is a little higher in the night sky and it will be available for good viewing through April.
Planetary Nebula NGC 3242 is
about 1400 light-years away.
Mu Hydrae is the brightest star close to the Ghost and is about 248 light years from Earth as compared to the Ghost’s 1400 light year distance. The Ghost of Jupiter was once a red giant that has expanded and ejected most of its outer layers. The remaining star shrinks back in size to become a white dwarf and the light that it produces causes the ejected gases to glow producing what looked like a large planet to early astronomers through their small optical telescopes which lead to the name of planetary nebula.
The image to the right has been enlarged to show the detail and also to show why this is sometimes referred to as the Eye Nebula.