Abell 31
Below: another rendition of the data, done in March 2022:
Abell 31 (or PK219+31.1) is an ancient planetary nebula in the constellation of Cancer. It is estimated to be about 2,000 light years away. Although it is one of the largest planetary nebulae in the sky, it is not very bright and not so easy to image. Its shape is caused by interaction with the interstellar medium, as it is moving through space at high speed. The PN was discovered in 1955 by George Abell on the POSS plates.
Some might find it interesting to note that the spiral galaxy IC523 (upper left in the annotated image below) is an estimated 386 million light years from the Milky Way.
For those with the time & interest, I have added an explanetary note below, on what a Planatary Nebula is. (Copied from Wikipedia).
Imaging telescope: Takahashi FSQ130ED
Imaging cameras: QSI 6120i
Mounts: Takahashi EM 400 Temma 2
Guiding cameras: QHY CCD QHY 5 II
Focal Extender / Reducer: Tak QE 0.73x used in Feb.
Software: PHD 2, Astro Pixel Processer, PixInsight , Sequence Generator Pro SGP
Filters: Astrodon Ha (5nm), OIII (5nm) & Astrodon RGB
Accessories: ATIK EFW2
Original Resolution: 2150 x 1468
Dates: Jan. 13 - Jan. 26, 2021 @ 0.98 ArcSec/Pix
Dates: Feb. 12 - Feb. 16, 2021 @ 1.36 ArcSec/Pix
Frames:
Astrodon Ha: 24x900" + 13x1200"
Astrodon OIII: 24x900" + 18x1200
Astrodon RGB: 45x120""
Integration: 23 Hours 30 Mins.
Center (RA, Dec):(133.560, 8.884)
Center (RA, hms):08h 54m 14.328s
Center (Dec, dms):+08° 53' 02.202"
Size:48.3 x 33 arcmin
Radius:0.487 deg
Pixel scale:1.35 arcsec/pixel
Orientation:Up is 97.9 degrees E of N
Some might find it interesting to note that the spiral galaxy IC523 (upper left in the annotated image below) is an estimated 386 million light years from the Milky Way.
For those with the time & interest, I have added an explanetary note below, on what a Planatary Nebula is. (Copied from Wikipedia).
Imaging telescope: Takahashi FSQ130ED
Imaging cameras: QSI 6120i
Mounts: Takahashi EM 400 Temma 2
Guiding cameras: QHY CCD QHY 5 II
Focal Extender / Reducer: Tak QE 0.73x used in Feb.
Software: PHD 2, Astro Pixel Processer, PixInsight , Sequence Generator Pro SGP
Filters: Astrodon Ha (5nm), OIII (5nm) & Astrodon RGB
Accessories: ATIK EFW2
Original Resolution: 2150 x 1468
Dates: Jan. 13 - Jan. 26, 2021 @ 0.98 ArcSec/Pix
Dates: Feb. 12 - Feb. 16, 2021 @ 1.36 ArcSec/Pix
Frames:
Astrodon Ha: 24x900" + 13x1200"
Astrodon OIII: 24x900" + 18x1200
Astrodon RGB: 45x120""
Integration: 23 Hours 30 Mins.
Center (RA, Dec):(133.560, 8.884)
Center (RA, hms):08h 54m 14.328s
Center (Dec, dms):+08° 53' 02.202"
Size:48.3 x 33 arcmin
Radius:0.487 deg
Pixel scale:1.35 arcsec/pixel
Orientation:Up is 97.9 degrees E of N
Sky Map
A note on Planetary Nebulae:
A planetary nebula, abbreviated as PN or plural PNe, is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.
The term "planetary nebula" is a misnomer because they are unrelated to planets or exoplanets. The term originates from the planet-like round shape of these nebulae observed by astronomers through early telescopes. The first usage may have occurred during the 1780s with the English astronomer William Herschel who described these nebulae as resembling planets; however, as early as January 1779, the French astronomer Antoine Darquier de Pellepoix described in his observations of the Ring Nebula, "very dim but perfectly outlined; it is as large as Jupiter and resembles a fading planet". Though the modern interpretation is different, the old term is still used.
All planetary nebulae form at the end of the life of a star of intermediate mass, about 1-8 solar masses. It is expected that the Sun will form a planetary nebula at the end of its life cycle. They are a relatively short-lived phenomenon, lasting perhaps a few tens of thousands of years, compared to considerably longer phases of stellar evolution. Once all of the red giant's atmosphere has been dissipated, energetic ultraviolet radiation from the exposed hot luminous core, called a planetary nebula nucleus (PNN), ionizes the ejected material. Absorbed ultraviolet light then energizes the shell of nebulous gas around the central star, causing it to appear as a brightly coloured planetary nebula.
Planetary nebulae probably play a crucial role in the chemical evolution of the Milky Way by expelling elements into the interstellar medium from stars where those elements were created. Planetary nebulae are observed in more distant galaxies, yielding useful information about their chemical abundances.
Starting from the 1990s, Hubble Space Telescope images revealed that many planetary nebulae have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms that produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.
A planetary nebula, abbreviated as PN or plural PNe, is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.
The term "planetary nebula" is a misnomer because they are unrelated to planets or exoplanets. The term originates from the planet-like round shape of these nebulae observed by astronomers through early telescopes. The first usage may have occurred during the 1780s with the English astronomer William Herschel who described these nebulae as resembling planets; however, as early as January 1779, the French astronomer Antoine Darquier de Pellepoix described in his observations of the Ring Nebula, "very dim but perfectly outlined; it is as large as Jupiter and resembles a fading planet". Though the modern interpretation is different, the old term is still used.
All planetary nebulae form at the end of the life of a star of intermediate mass, about 1-8 solar masses. It is expected that the Sun will form a planetary nebula at the end of its life cycle. They are a relatively short-lived phenomenon, lasting perhaps a few tens of thousands of years, compared to considerably longer phases of stellar evolution. Once all of the red giant's atmosphere has been dissipated, energetic ultraviolet radiation from the exposed hot luminous core, called a planetary nebula nucleus (PNN), ionizes the ejected material. Absorbed ultraviolet light then energizes the shell of nebulous gas around the central star, causing it to appear as a brightly coloured planetary nebula.
Planetary nebulae probably play a crucial role in the chemical evolution of the Milky Way by expelling elements into the interstellar medium from stars where those elements were created. Planetary nebulae are observed in more distant galaxies, yielding useful information about their chemical abundances.
Starting from the 1990s, Hubble Space Telescope images revealed that many planetary nebulae have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms that produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.
Annotated Image
