NGC 6543
The Saturn Nebula - NGC 7009
NGC 7009 is a planetary nebula located in the direction of the constellation Aquarius, the water bearer or cup bearer. The nebula was discovered by William Herschel September 7th, 1782 using his own telescope design. Later Hershel would design a 40-foot telescope with a 48 inch mirror financed using £4000 from King George III who once referred to this new largest telescope on earth as "The Way to Heaven". The NGC 7009 nebula was later called the Saturn Nebula by Lord Rosse in the mid 1800s due to its visual resemblance to the planet Saturn as viewed through the greatly improved telescopes at the time. Its similarity to Saturn stops there however, as the nebula is actually caused by an aging star ejecting its material into space in layers. The central star visible in the image is now a white dwarf that is both lighting and exciting the surrounding material. The Saturn Nebula is very complex with many features including the ansae or “handles” appearing as edge-on rings that give it its name. These ansae are moving directly away from the center and are also a similar feature visible in the NGC 6543 image. Measuring distances to planetaries are often difficult due to the diversity of their size and brightness, however, the distance to the Saturn Nebula is probably about 5000 light years, giving it a size of between 0.5 and 1 light year across. The central star is actually a hot blue dwarf emitting strongly in the ultraviolet spectrum. A surprise bonus that appears in this image is the asteroid 3572 Leogoldberg discovered in the 1950s by the American astronomer and Harvard professor Leo Goldberg. It appears as a faint line at the bottom of the image. I initially thought it a flaw in one of the camera images, but after examining more images and referring to JPL/NASA maps and tools I discovered it to be an asteroid. It was moving way too slowly over the 3 hour imaging time to be an earth based satellite and the fact that it moved at all relative to the other stars proved it was not a star. The asteroid is about 9 km in diameter and orbits between Mars and Jupiter in the infamous asteroid belt region. The Saturn Nebula is very close to the ecliptic, the imaginary plane where all the planets and most asteroids in the solar system reside. This location makes it much more likey to accidentally image an asteroid than at other places of the sky. In fact there were 6 other asteroids in this field of view, but at 100 times fainter, were just too faint to easily show up on the image. The stats for NGC 7009 are as follows: RA 21h 04m 11s, Dec -11° 21' 49", Mag 8.3, Size 70.0", Mag Central Star 11.5
Optics: RC Optical System 20" F/8.2 (4165.6 mm Focal Length) Date: September 18th, 2020
Camera: SBIG STXL-11000 with AO-X Adaptive Optics Location: Columbus, Texas
Exposure: LRGB = 120-:21:24:27 minutes Imager: Kent E. Biggs

NGC 6543