NGC 7009, also known as Caldwell 55, is a planetary nebula in the constellation Aquarius, which is best viewed in autumn.
You may wonder if there is a relationship between the nebula and the planet Saturn. The answer is no. In the 1840s, the Irish astronomer Lord Rosse noticed the resemblance to Saturn’s shape and named it. Before that time, the telescopes were not powerful enough to resolve the bulges on the sides of the nebula. Credit goes to William Herschel for discovering NGC 7009 six decades early on September 7, 1782, from his home garden in Datchet, England.
A dying low-mass star created NGC 7009 as it expanded and then expelled gas as part of the process. The star eventually shrunk down to what it is today: a very hot white dwarf star that continually irradiates the surrounding gas, giving the nebula its green hue. The star will eventually fade away, as NASA puts it, like a “hot coal that glows after a barbecue.” 1
My Observations
| Date | September 1, 2022 |
| Time | 9:55 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Average |
| Transparency | Average |
Tonight is my first time out under the stars since my daughter left for college. I’m still adapting to having a quieter house, and I miss her terribly. In moments like these, I’d usually call her and my wife out to the backyard to look through the scope at new finds like this Saturn Nebula. I did just text my wife to come see it.
I’m surprised this is my first time observing NGC 7009 (Saturn Nebula). For some reason, I’d always thought it was too dim and small to see from the city. However, tonight proves me wrong. I’m surprised how well my scope is resolving the object as a light-blue haze, which may also have a tinge of green. The 12mm eyepiece is a perfect match with my 8-inch SCT for this nebula. The nebula remains bright and sharp enough, while not being too small.
Key Stats
| Constellation | Aquarius |
| Best Viewing | Autumn |
| Visual Magnitude | +7.9 |
| Absolute Magnitude | -2.2 |
| Distance from Earth | 1,400 ly |
| Diameter | .5 ly |
| Apparent Size | .5 x .4 arcmin |
| Milky Way Location | Orion Spur |
| My Viewing Grade | B+ |
Sources and Notes
The banner photo of NGC 7009 was produced by the European Southern Observatory (ESO). According the ESO website, this unaltered image is licensed under a Creative Commons Attribution 4.0 International License. The original file is here: https://www.eso.org/public/images/eso1731a/.
Portrait of William Parsons Earl of Rosse is from The Royal Society collection and part of the public domain. Reference artuk.org for more information.
1 Henderson, Edward. “Caldwell 55.” NASA, NASA, 2 Dec. 2019, https://www.nasa.gov/feature/goddard/caldwell-55.
AKA: Caldwell 55, ARO 16, C 55, W259
The Garden Astronomer 
2 thoughts on “NGC 7009: The Saturn Nebula”