NGC 1501 is a complex planetary nebula located in the constellation of Camelopardalis
Discovered by William Herschel in 1787, NGC 1501 is a planetary nebula that is just under 5,000 light-years away from us. Astronomers have modeled the three-dimensional structure of the nebula, finding it to be a cloud shaped as an irregular ellipsoid filled with bumpy and bubbly regions. It has a bright central star that can be seen easily in this image, shining brightly from within the nebula’s cloud. This bright pearl embedded within its glowing shell inspired the nebula’s popular nickname: the Oyster Nebula.
While NGC 1501's central star blasted off its outer shell long ago, it still remains very hot and luminous, although it is quite tricky for observers to spot through modest telescopes. This star has actually been the subject of many studies by astronomers due to one very unusual feature: it seems to be pulsating, varying quite significantly in brightness over a typical timescale of just half an hour. While variable stars are not unusual, it is uncommon to find one at the heart of a planetary nebula.
Explanation: "Nebula at the right foot of Andromeda ... " begins the description for the 76th object in Charles Messier's 18th century Catalog of Nebulae and Star Clusters. In fact, M76 is one of the fainter objects on the Messier list and is also known by the popular name of the "Little Dumbbell Nebula". Like its brighter namesake M27 (the Dumbbell Nebula), M76 is recognized as a planetary nebula - a gaseous shroud cast off by a dying sunlike star. The nebula itself is thought to be shaped more like a donut, while the box-like appearance of its brighter central region is due to our nearly edge-on view. Gas expanding more rapidly away from the donut hole produces the fainter loops of far flung material. The fainter material is emphasized in this composite image, highlighted by showing emission from hydrogen atoms in orange and oxygen atoms in complementary blue hues. The nebula's dying star can be picked out in the sharp false-color image as the blue-tinted star near the center of the box-like shape. Distance estimates place M76 about 3 to 5 thousand light-years away, making the nebula over a light-year in diameter.
"NGC 40 is a bright planetary nebula consisting of a detailed core with an outer halo. This halo consists of a double structure with a diffuse inner halo attached to the central shell and a more irregular filamentary structure, which extends to the north. In addition to these array of features is a structure to the south, which has been interpreted as a jet. Professional observations with the Spitzer infrared telescope have shown the inner halo to consist of multiple overlapping radial spoke ring structures. This halo was discovered in 1987.
The central star of this planetary nebula has been well studied by professional astronomers and is also interesting in its own right. It belongs to the Wolf Rayet subclass of planetary nebula central stars that are hydrogen deficient and exhibit high mass loss rates and strong stellar winds. WR type central stars have been identified in a number of other planetary nebulae including IC 4663 and Abell 48.
Extending along the contours of the full field of this image are multiple colourful filaments belonging to the large faint supernova remnant CTA 1, which covers an area of 1.5 degrees across the sky. Both NGC 40 and CTA 1 are physically unrelated with the supernova remnant lying more distant in the background. NGC 40 is 3500 light years away and CTA 1 is 4500 light years away."
Cats Eye Nebula (SWO)
Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its more familiar outlines are seen in the brighter central region of the nebula in this impressive wide-angle view. But the composite image combines many short and long exposures to also reveal an extremely faint outer halo. At an estimated distance of 3,000 light-years, the faint outer halo is over 5 light-years across. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. More recently, some planetary nebulae are found to have halos like this one, likely formed of material shrugged off during earlier episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years. Visible on the left, some 50 million light-years beyond the watchful planetary nebula, lies spiral galaxy NGC 6552.
CaVa 1 Planetary Nebula (SWO)
"CaVa 1 is an obscure ancient planetary nebula that was discovered by the French amateur astronomers Jean-Paul Cales and Michael Vanhuysse in 2017. It has a size of 8x7 arcminutes and is located in a region of background nebulosity. There is sometimes a relation between the size of a planetary nebula, its age and its relative faintness. Older planetary nebulae over time eventually expand more and the ionizing energy is spread over a larger area as well as the density of the gas being thinner, so therefore exhibit lower surface brightness. This is easily overcome by amateur astronomers who are able to obtain very long exposures. Large low surface brightness planetary nebulae have been discovered in professional Ha surveys and also by amateurs analysing various astronomical survey data.
CaVa 1 consists of primarily Ha emission with some OIII in its interior. The southern part exhibits a tenuous bowshock structure produced by its interaction with the surrounding interstellar medium (ISM). Few examples of planetary nebulae with ISM interaction are known due to their extremely low intrinsic brightness. This stage in the evolution of a planetary nebula precedes the total dilution and fading of a planetary nebula. However, the phenomenon of ISM interaction has been observed in young planetary nebulae with high speed central stars and studies conclude that different stages of interaction are exhibited throughout the life of planetary nebulae. The idea of a planetary nebula interacting with the ISM as it moves through space was proposed in 1969 by the Armenian astronomer Grigor Gurzadyan."
PuWe1 (PNG 158.9 + 17.8), in Lynx (SWO)
PuWe1 (PNG 158.9 + 17.8), in Lynx, is one of the largest PN, that has an apparent diameter of 20'. It has been discovered by Purgathofer & Weinberger in 1980 on a Palomar sky survey print. As almost all this kind of old diluted PN, it is very faint and requires long exposures to get details. The Halpha signal is the strongest and draws a ring with several details in the structure while the OIII signal is extremely faint with a disc shape and no visible structure.
PK 164+31.1 Jones-Emberson 1 (SWO)
PK 164+31.1 Jones-Emberson 1
Explanation APOD: Is this what will become of our Sun? Quite possibly. The bubble of expanding gas pictured above is the planetary nebula PK 164 +31.1, the remnants of the atmosphere of a Sun-like star expelled as its supply of fusion-able core hydrogen became depleted. Visible near the center of the nebula is what remains of the core itself -- a blue-hot white dwarf star. This particularly photogenic planetary nebula shows intricate shells of gas likely expelled at different times toward the end the star's demise, and whose structure is not fully understood. This deep image of PK 164 +31.1 shows many other stars from our own Milky Way Galaxy as well as several galaxies far in the distance. PK 164 +31, also known as Jones-Emberson 1, lies about 1,600 light years away toward the constellation of the Wildcat (Lynx). Due to its faintness (magnitude 17) and low surface brightness, the object is only visible with a good-sized telescope. Although the expanding nebula will fade away over the next few thousand years, the central white dwarf may well survive for billions of years -- to when our universe may be a very different place.
Telescope: Planewave 24" f6.7 on a Planewave HD Mount Camera: SBIG 16803
Location: Stellar Winds Observatory at DSNM, Animas, New Mexico
Exposure: L,R,G,B,HA,03 500,210,210,210,1350,1440 65Hours of exposure so far. Still working on the O3 data.
Ferrero 6 (Fe 6)PN G129.6+3.4 (SWO)
Ferrero 6 (Fe 6, PN G129.6+03.4) Planetary Nebula in Cassiopeia. The bright blue star above the nebula is BD+64 263 (SAO 12045). This PN was identified by Laurent Ferrero in November 2013.
The Soap Bubble Nebula PN G75.5+1.7 (SWO)
The Soap Bubble Nebula PN G75.5+1.7
Explanation From APOD:
Adrift in the rich star fields of the constellation Cygnus, this lovely, symmetric nebula was only recognized a few years ago and does not yet appear in some astronomical catalogs. In fact, amateur astronomer Dave Jurasevich identified it as a nebula on 2008 July 6 in his images of the complex Cygnus region that included the Crescent Nebula (NGC 6888). He subsequently notified the International Astronomical Union. Only eleven days later the same object was independently identified by Mel Helm at Sierra Remote Observatories, imaged by Keith Quattrocchi and Helm, and also submitted to the IAU as a potentially unknown nebula. The nebula s now known as the Soap Bubble Nebula. Most probably it is a planetary nebula, a final phase in the life of a sun-like star.