A gravitational lens, as predicted by Einstein general theory of relativity, is a distribution of matter or a point particle between a distant light source and an observer, and such matter is capable to bending light from the source as light travels toward the observer, and although Einstein made unpublished calculations in 1912, Khvolson 1924 and Link 1936 officially first discussed the effect of gravitational lens, however the official study is more commonly associated to Einstein 1936.
Cfr. : Khvolson O. 1924 : Über eine mögliche Form fiktiver Doppelsterne “ in Astronomische Nachrichten 221 (20): 329-330
Einstein A. 1936 “Lens-like action of a star by the deviation of light in the gravitational field” in Science 84 (2188):506-507
Unlike an optical lens, a point-like gravitational one produces as maximum deflection of light as the closest light passes to its center, and a minimum furthest from it, consequently scholars commonly agree that such gravitational lens has no focal point but focal line.
Observations in fact demonstrated that if the light source, the massive matter acting as a lens, and the observer all lie in a straight line, the original source will appear as a ring around the massive lensing object named “Einstein ring”, or “Einstein–Chwolson ring” or “Chwolson ring “: ring effect was first mentioned in the academic literature by Orest Khvolson in previously mentioned article of 1924, in which he mentioned the “halo effect” of gravitation when the source, lens, and observer are in near-perfect alignment.
Misalignment between the observer, matter lens and source of light will be appreciate by observer like an arc segment.
Ring-like structure, size, and family of multiple source of light geometry observation and measurement:
The geometry of a complete Einstein ring, caused by a gravitational lens with the size given by the Einstein radius.
Micro lensing techniques have been used to search for planets outside our solar system, as for instance according to Cassan et al. 2012 statistical analysis of specific cases of observed microlensing over a period of 2002 to 2007 found that most stars in the Milky Way galaxy hosted at least one orbiting planet within 0.5 to 10 astronomical units.
Cfr. Cassan A. , Kubas D. , Beaulieu J. , Dominik M. , Horne K. , Greenhill J. , Wambsganss J. , Menzies J. , Williams A. 2012 “One or more bound planets per Milky Way star from microlensing observations” in Nature 481 (7380):167-169
Galaxy cluster
According to Atek et al. 2015 galaxy clusters can be considered as the most massive structure in actual known Universe and are therefore powerful cosmic instruments for observing faint and distant sources via gravitational lensing effect.
As indicated by Caminha et al. 2016b and by Vanzella et al. 2020, 2021, lensing magnification obtained by observing trough galaxy cluster can reach factors of ~ 100 – 1000, as when a background source of light, i.e. a galaxy, lies between observer and galaxy cluster, light rays from the sources are deflected by gravitational potential of the foreground cluster; source is thus gravitationally lenses by the cluster.
Moreover, as suggested by Bradač et al. 2006 and by Clowe et al. 2006, position and morphologies of multiple lensed images also allow to speculate about the distribution of matter, particularly dark matter, in the galaxy cluster, crucial topic for understanding nature of dark matter.
Julio et al. 2010, Acebron et al. 2017, Caminha et al. 2016a and 2022 pushed further, as an individual galaxy cluster often lenses several background sources into several corresponding “families” of multiple images that straddle different locations around the galaxy cluster, and families of multiple images formed by sources in different redshift provide possible measurements of angular diameter distance ratios between cluster and source, allowing researchers to focus about the study of the geometry of the universe.
Refsdal 1964; Suyu et al. 2010; Kelly et al. 2015; Grillo et al. 2018 and 2020 believe that strong lensing galaxy clusters are therefore excellent laboratories for astrophysical and cosmological studies as in case where a background source is timy-varying, as a quasar or a supernova, the time delays between multiple images study provides to speculate measurements of the “time-delay distance” and the Hubble constant that sets the expansion rate of actual known Universe.
According to Rigby et al. 2022, James Webb Space Telescope operating in infrared provides unprecedented observation of high-redshift sources in terms of sensitivity and angular resolution.
Combination of JWST capacities and galaxy cluster lensing consent to observe inherently faint sources like distant galaxies which are the first formed and which evolved into structures that we see today.
Among these targets JWST focused on its first cosmic target to galaxy cluster SMACS J0723.3-7327 discovered by Ebeling et al. 2001 and Repp & Ebeling 2018.
According to Caminha et al. 2022 JWST observations practically doubled number of families of multiple images previously detected by Hubble Space Telescope.
Hubble observations of SMACS J0723 cover an area of 3.36 arcmin x 3.36 arcmin and were obtained by f435w, f606w and f814w filters of ACS – Advanced Camera for Surveys, and in f105w, f125w, f140w and f160w of WFC3 – Wide Field Camera 3 all available and retrieved at Mikulski Archive.
Caminha et al. 2017b, 2019 and 2022 produced by Hubble data plus MUSE data of SMACS J0723 a final redshift catalogue containing 78 secure and precise redshift measurements.
SMACS J0723 was observed by James Webb scope by Near Infrared Camera – NIRCam and MIRI – Mid-Infrared Instrument and spectroscopy was obtained trough the NIRSpec – Near Infrared Spectrograph.
According to Pontoppidan et al. 2022 and Méndez-Abreu et al. 2023, with a single filter total exposure of about 7.500 seconds divided in nine dither patterns to optimize image quality NIRCam records were taken on 2022 June 7th, carried out in filters f090w, f150w, f200w, f277w, f356w and f444w, covering a wavelength range between 0.8nm to ~ 5.0nm.
Webb scope NIRCam FoV observes a 9.7 arcmin 2 (al quadrato) field with a ~44 arcsec gap separating two 2.2 arcmin x 2.2 arcmin areas, with one camera centers on the cluster and another on an adjacent field, covering a smaller area of J0723 respect to Hubble imaging.
According to Caminha et al. 2022, Webb Scope NIRCam wavelengths and high spatial resolution records, aligned to HST data took to identify new 30 additional secure multiple images from 11 individual sources, extremely faint or not detected in the Hubble optical and near infrared imaging, whilst Before the release of James Webb scope NIRCam imaging of SMACS J0723 dataset available from Hubble plus photometry from RELICS program and spectroscopy from MUSE identified 23 cluster members in the redshift range of 0.367 – 0.408 corresponding to a rest-frame velocity of + – 3000 km/s from the cluster mean redshift of z=0.387; these pre JWST studies evinced according to Caminha et Al. 2022 in 19 multiple images as input from six families.
In conclusion, Webb scope actual studies of NIRCam records focused about SMACS J0723 scholars have doubled the number of model constraints, increasing the number of multiple images from the 19 identified with Hubble and MUSE datasets to 49.
According to Méndez-Abreu and colleagues 2023 observations obtained by NIRCam provides new data in the study of the evolution of barred galaxy, as the central role of stellar bars in the secular evolution of galaxies discs is generally accepted: as founded by Hubble 1926 and Buta et al 2015 they represent the main structure modifying the morphology of galaxies in the central ~ kpc and according to Debattista & Sellwood 2000, Martinez-Valpuesta et al. 2007 and Sellwood 2014 they influence the angular momentum redestribution between the baryon of and dark matter component of galaxies.
Evolution of the bar fraction with cosmic time has been matter of several studies due to its implications on the settlement of the first rotationally dominated discs. According to Sellwood 2014 and Méndez-Abreu 2023 bars can be formed spontaneously in cold galaxy discs in a relative quick phase (<=1 Gyr) and assuming as right as they are long lived, the presence of a bar can be used as a clock to time the formation of discs.
Martinet & Friedli 1997, Sheth et al. 2005, Ellison et al. 2011 identify in galaxies bars the parts with the ability to funnel material towards the galaxy core where starburst can ignite; Kormedy & Kennicut 2004, Athansas-soula 2005, Bittner et al. 2020 with Gadotti et al. 2020, all agree that they contribute to the formation of bulge-like structures.
Buta 1995, Muñoz-Tuñón et al. 2004 identifies in bars the main inner star forming ring’s cause.
Importance of bars in understanding galaxy evolution is also given by their ubiquity in disc galaxies in the local Universe (z < 0.1) with actual galaxy population optical studies generally described as barred by ~50%, with slight increase by infrared observations; Cfr. Aguerri et al. 2009; sbarazza et Al. 2008, Eskridge et al. 2000, Marinova & Jogee 2007, Menéndez-Delmestre et al. 2007, Erwin 2018.
According to Méndez-Abreu and colleagues 2023 most of our knowledge about the formation and evolution of bars has been produced using local galaxy samples, and studying SMACS J0723.3-7327 galaxy cluster using the new capabilities of Webb scope coincides with the possibility of measure the fraction of barred galaxies in a cluster with redshift z=0.39, and NIRCam imaging features overcome previous problem of spatial resolution, bar identification at rest-frame wavelengths, and depth of the observations.
Méndez-Abreu et al 2023 studies for barred galaxies identification and classification started from NIRCam f200w filter integration master, with first step as identification of cluster J0723 members, consisting in 188 certain galaxies.
Identification of bars was made by Méndez-Abreu setting up a private project using the Zooniverse Panoptes Project Builder, creating .fits cutouts of cluster members and converting each one in a single arcsinh stretched frame, with the result of 20 secure barred galaxies and 15 uncertain out of 188 members.
Méndez statistical analysis shows that bar fraction distribution in SMACS J0723 cluster is a strong function of galaxy mass, results which compared with the state of art of observational and theoretical studies appears little increasing, probably dued both to different criteria in selection (angular momentum vs morphology) and improved capabilities of JWST/NIRCam respect to previous instrument in terms of spatial resolution and image depth.
The mechanism inhibiting the formation of bars in cluster seems act relatively quickly after galaxies enter into the cluster potential, with a scenario where cluster environment affects the formation of bars in a mass-dependent way. At high masses it seems plausibile to assert a weak effect of cluster environment possibly triggering bar formation, whilst at low masses galaxies bars formation seems to be severely inhibited by cluster setting.
During 2021 and 2022 I took a good number of subframes focusing on M81 and M82 field and I planned to integrate RGB channels with Ha and Oiii narrowband contribute.
Being a follower of John Rista short time DSO photography approach, RGB channel subframes I recorded at 60″, Halpha and Oiii subframes at 180″, William Optics Redcat51 and ASI1600mm Pro at -20 Celsius, Gain 139.
After standard calibration, cosmetic correction by dark-master, star registration and winsorized sigma clipping integration, I obtained masterframe for each channel recorded.
Channel combination of RGB generated a good integration which I played with Ha and Oiii masters to Dynamic BG removal, solving (and annotated transparent layer version for further work), Spectrophotometric Color Calibration (just RGB) deconvolution and denoising.
I then proceed by starXterminator in starless and stars version of each master to work properly ‘till putting them back by PixelMath, obtaining a pretty good RGB master
with ready-to-go Halpha and Oiii narrowband master to integrate within:
H alpha channel to be associated to R channel while Oiii to differently be integrated with both G and B channels.
Narrowband with RGB integration produced a pretty good result which, in turns, I little worked over separating again stars and starless sub-master, finally directly melted in Photoshop.
This portion of sky is so rich of galaxies; PGC annotation (PixInSight) gives an idea of the richness of field
I thus start to try some crop solution for better framing and focusing the final image. At first I cropped a squared and a vertical version to catch in the field also NGC2976, NGC2961 and NGC2959.
Finally I focused about M81 and M82 with a deep cropping for an orizontal composition, trying to dispose M81 and friends according to 3/4 grids basic composition rule.
Photoshop, non cropped version, with 3 main crops framing as guide layer are available here
According to Stewart Sharpless annotation, 1959 “A Catalogue of Hii Regions” U.S. Naval Observatory, 10 Sept. 1959 [ https://articles.adsabs.harvard.edu/pdf/1959ApJS….4..257S ], Sh2-139 is “Part of II Cep association” a wide and luminous OB spectral type stellar association situated at a distance of about 3.200 parsec, or 10.400 light years, within the Perseus Arm, one of the 2 major spiral arms of our galaxy.
Cfr.: Churchwell Ed, Babler Brian L., Meade Marlin A. 2009 “The Spitzer/GLIMPSE Surveys: A New View of the Milky Way” Publications of the Astronomical Society of the Pacific. 121: 213–230. https://ui.adsabs.harvard.edu/abs/2009PASP..121..213C/abstract
Sh2-132 complex is featured by a bright optical nebula with an intense central region (Ø = 25’) surrounded by more diffuse emission ( Ø ~ 1*). Low resolution radio studies have shown it to be an intense radio source with a strong central core contained into a more diffuse envelope.
Churchwell and Walmsley 1973 analysis confined that the total emission is thermal nature, featured by a spectrum flatted down to 0.408 GHz, typical of a low Hii density region.
Cfr. Churchwell E. , Walmsley C. M. , 1973 “Observation of Optical Nebula at 2695 Mhz ” in Astron. Astrophys. 23: 117
Nebula analysis shows two distinct regions separated by an area, running from NW to SE, with little or no emission.
The optical emission in the eastern region is quite mottled, with areas of bright emission and patches of obscuring materials. Western region is instead featured by little or no obscuring matter.
Strong central features and western/eastern regions strong/weaker emission are confirmed by radio analysis at 0.408 GHz and 1.4 GHz conducted respectively by Felli et al. 1977a and Felli and Churchwell 1972.
According to Van der Hucht 2001 and Hamman et al. 2006 among those very hot and massive stars responsible for the ionization of gasses, notable consideration have to be taken about two Wolf-Rayet subjects, known as HD 211564 and HD 211853 (or WR 153), featured by a huge bubble well visible in radio emissions identified as Shell B, which scholars suggest to be originated from strong stellar wind from these massive star, featured after Harten et al. 1978 study by a non uniform emission specially on the eastern side where there is essentially no emission at all.
Similar smaller structure, named Shell A, bubbles around a class K star.
According to Dubout-Crillon 1976 catalogue, lion’s bottom and tail shaped like portion is made by a thin strip of emission extending to the south of the eastern region featured by a faint Halpha ridge.
Cfr. Dubout-Crillon R. 1976 “H II regions of the northern Milky Way: medium-large-field photographic atlas and catalogue” in Astronomy and Astrophysics, Suppl. Ser., Vol. 25, p. 25 – 54. https://adsabs.harvard.edu/full/1976A%26AS…25…25D
According to Avedisova 2002 it is plausible to hypothesize that this nebula was setting of some chain processes of star origin.
Harten et al. 1978 studies of radio emission of this Hii region results indicated that 2/3 of the radio emissions originates in features larger then 10’ in diameter, suggesting that total mass and low electron density placed Sh2-132 as a member of evolved giant Hii region.
Helou and Walker studies of infrared sources identified and cataloged within the nebula nine sources of infrared radiation, while Wouterloot and colleagues 2013 identified an H2O maser source.
Helou, George; Walker, D. W., Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 7: The small scale structure catalog, in Infrared astronomical satellite (IRAS) catalogs and atlases, vol. 7, 1988, pp. 1-265. https://ui.adsabs.harvard.edu/abs/1988iras….7…..H/abstract
Wouterloot, J. G. A.; Brand, J.; Fiegle, K., IRAS sources beyond the solar circle. III – Observations of H2O, OH, CH3OH and CO, in Astronomy and Astrophysics Supplement Series, vol. 98, n. 3, maggio 1993, pp. 589-636. URL consultato il 21 marzo 2013. https://ui.adsabs.harvard.edu/abs/1993A%26AS…98..589W/abstract
The development of infrared astronomy gives chances to scholars like Saurin and colleagues 2009 to explore Sh2-132 Hii regions and studied its Hii region as a star forming region and embedded star clusters complex.
Grounding on Harten et al. 1978 radio continuum emission as indication of giant nature of this complex and its evolved character, Saurin hypothesized that Sh-132 could be suitable laboratory for early dynamical and hydrodynamical evolution, and by R-band Digitalized Sky Survey imaging of the whole complex they confirm 2 previous identified open cluster
Teutsch 127a – optical embedded open cluster, includes Trap 900
and Berkley 94a – optical open cluster on the outskirts of the complex
And discovered 4 new open cluster:
SBB1 – infrared embedded cluster with IRAS 22172+5549,
SBB2 – optical embedded cluster with bow-shock
SBB3 – Compact optical open cluster surrounding WR 152
SBB4 – Optical open cluster on the outskirts of the complex.
According to Greg T. Bacon of the Space Telescope Science Institute of Baltimora [ https://webbtelescope.org/contents/media/videos/1097-Video 20/07/2023 ] stars cluster belonging to M16 consist in a group of around 8.000 formed roughly 5.5 milion years ago, immersing within a cloud of gas and dust illuminated by the central cluster of bright youngest new formed stars.
The Pillars of Creation sit inside this wide region of gas and dust being pushed from the inside out by powerful stellar winds.
The winds blow back the edges of the cloud, creating dense regions that then collapse under their own gravity to form stars.
The characteristic fingers of the Pillars are some of the densest gas in this region, hanging on against the strong winds.
In the visible-light view they are entirely in shadow: such visible-light gazing shows the illumination of the inside of the gas and dust.
James Webb scope focused about the iconic Pillars of Creation, immense towers carved out of the cold dust by high-energy electromagnetic radiation emitted by the hot stars.
Webb NIRCAM eye investigating the pillars of gas and dust which block visible light, reveals what is under nebulosity concealing, with stars forming within them shining of infrared light through the dust-block, revealing stars forming within the pillars as well as stars far beyond; X-ray light also shines through the pillars, revealing extremely hot stars, most of which lie beyond the nebula.
NIRCAM Near-Infrared shows cooler towers and field of dust with many young stars.
MIRI records pointing at the bottom left shows the thickest regions of gas and dust, which appear light blue and dark gray-blue: there are many layers of semi-opaque gas and dust overlaying one another.
The first pillar points to the top right of the image.
There is one prominent red star, with tiny spikes at its tip.
Lower on this pillar, which forms a diagonal from bottom left to top right, there are several darker areas of dust that jut out, many with bright red stars, which appear as small red dots.
Below the top pillar are two slightly smaller, both ending in dark gray-blue regions: the second pillar has a dark arch that looks like an upside-down L halfway down, while the third pillar is set off in dark blue and gray shades.
At the bottom left is another overlapping area of gas and dust that forms a peak, but is also colored in various shades of gray and light blue.
Background of this scene is washed in shades of deep red and light red. Toward the top center, a V shape appears above the top-most pillar. At its lowest point, it is brilliant red. There are only several dozen tiny bright white and blue stars. Larger stars appear redder and are embedded in the pillars.
According to Claire Blome and Christine Pulliam – Space Telescope Science Institue of Baltimore – Mid-infrared light set such a somber, chilling mood in Webb’s Mid-Infrared Instrument (MIRI) because interstellar dust cloaks the scene, and while mid-infrared light specializes in detailing where dust is, the stars aren’t bright enough at these wavelengths to appear. Instead, these looming, leaden-hued pillars of gas and dust gleam at their edges, hinting at the activity within.
*** Processing method ***
.fits level 3 calibration raw data I downloaded from mast.stsci.edu portal.
NIRCAM set is made of 6 .fit image recording pillars by filter f090w, f187n, f200w, f335m, f444w and f444w+f470n.
After linear fit to f200w band, according to NIRCAM filters guideline, I considered f444w and f470n as the highest signal available, to be processed as red in colour mapping.
Blue mapping I assigned to the lowest band records available, thus melting f090w and f187n in PixelMath; the same for f200w and f335m melting for the middle signal green color in rgb layout.
RGB channel combination produced a greenish dominated master, processed in PixInSight by very soft bg removal, denoising workflow, starXterminator work for starless and stars separate file.
I thus focused on starless master for color manipulation by color mask and curves transformation, dark area enhancing, denoising and final blurxTerminating for details revelation.
I finally reconstructed starry image in Photoshop by screen blending mode of stars layer group over starless one, with each group adjustement and pixel-fixing independetly made.
MIRI image followed a similiar processing work, with peculiar feature of very very intense pixel fixing intervent, both in stars and starless level.
Starless image after pixel fixing and color calibration I find simply astonishing.
Starry final image reconstruction with few adjustements intervent
M16 (NGC 6611) Eagle Nebula, or Star Queen Nebula, was discovered in 1745 by the Swiss astronome Jean-Philippe de Cheseaux while in 1745 and 1746, De Chéseaux compiled a list of 21 nebulous objects, of which he had originally discovered 8 objects: IC 4665, NGC 6633, M16, M25, M35 (this one might have seen before by John Bevis in England), M71, M4, and M17. Moreover, he independently re-discovered M6, NGC 6231 and M22 (No. 17).
De Chéseaux sent this list to his grandfather, Reaumur, in Paris, and it was read by Reaumur at a meeting of the French Academy of Sciences on August 6, 1746 and mentioned by Jean Maraldi in 1746 (Maraldi 1751), by Le Gentil in 1759 (Le Gentil 1765), but then stayed unpublished and more or less forgotten until Guillaume Bigourdan recovered and published it within a larger paper in 1884 (Bigourdan 1892).
M16 was independently rediscovered, and nebula IC 4703 discovered, by Charles Messier on June 3, 1764.
This nebula lies in the Sagittarius Arm of the Milky Way and became famous as the “Pillars of Creation” imaged by the Hubble Space Telescope.
The nebula contains several active star-forming gas and dust regions, and is part of a diffuse emission nebula H II region, which is catalogued as IC 4703.
This region of active current star formation is about 5700 light-years distant.
According to NASA, ESA, and The Hubble Heritage Team (STScI/AURA) [ https://esahubble.org/images/heic0506b/ ] among peculiarities there’s the 90 trillion kilometers long spire of gas that can be seen coming off the nebula in the northeastern part appearing like a winged fairy-tale creature poised on a pedestal, this object is actually a billowing tower of cold gas and dust rising from a stellar nursery called the Eagle Nebula.
The name “Pillars of Creation” explains the gas and dust disposed in pillars clouds which are in the process of creating new stars, while also being eroded by the light from nearby stars that have recently formed, and it was given after the Hubble picture taken on April 1, 1995.
Astronomers responsible for the photo were Jeff Hester and Paul Scowen from Arizona State University.
According to DeVorkin and Smith, 2015 [Devorkin, David H.; Smith, Robert W., 2015 “The Hubble Cosmos: 25 Years of New Vistas in Space.” National Geographic Society: 67 this name is based on a phrase used by Charles Spurgeon in his 1857 sermon “The Condescension of Christ”: by calling the Hubble’s spectacular image of the Eagle Nebula the Pillars of Creation, NASA scientists were tapping a rich symbolic tradition with centuries of meaning, bringing it into the modern age.
As much as we associate pillars with the classical temples of Greece and Rome, the concept of the pillars of creation – the very foundations that hold up the world and all that is in it – reverberates significantly in the Christian tradition. When William Jennings Bryan published The World’s Famous Orations in 1906, he included an 1857 sermon by London pastor Charles Haddon Spurgeon titled “The Condescension of Christ”. In it, Spurgeon uses the phrase to convey not only the physical world but also the force that keeps it all together, emanating from the divine: “And now wonder, ye angels,” Spurgeon says of the birth of Christ, “the Infinite has become an infant; he, upon whose shoulders the universe doth hang, hangs at his mother’s breast; He who created all things, and bears up the pillars of creation, hath now become so weak, that He must be carried by a woman!”
According to Bally et. Al., the pillars are composed of cool molecular hydrogen and dust that are being eroded by photoevaporation from the ultraviolet light of relatively close and hot stars. The leftmost pillar is about four light years in length. The finger-like protrusions at the top of the clouds are larger than the Solar System, and are made visible by the shadows of evaporating gaseous globules (EGGs), which shield the gas behind them from intense UV flux.[10] EGGs are themselves incubators of new stars.
The stars then emerge from the EGGs, which then are evaporated.
Cfr.: Bally, J.; Morse, J.; Reipurth, B. (1996). “The Birth of Stars: Herbig-Haro Jets, Accretion and Proto-Planetary Disks”. In Benvenuti, Piero; Macchetto, F.D.; Schreier, Ethan J. (eds.). Science with the Hubble Space Telescope – II. Proceedings of a workshop held in Paris, France, December 4–8, 1995. Space Telescope Science Institute. https://ui.adsabs.harvard.edu/abs/1996swhs.conf..491B/abstract [18/07/2023]
Sh2-129 emission nebula presents an irregular ring-arch form which resemble a figure of a flying bat, and according to Blitz et.Al. is situated at a distance of about 400 parsec or 1300 light-years.
According to Dobashi and collegues the region sourroundig Sh-129 is particularly rich of molecular clouds, first among all the whide obscure nebulositys system occulting the Milky Way in the direction of Cefeus; cfr. Dobahashi K. et Al., 1994 “Molecular Clouds in Cygnus. I. A Large-Scale 13CO Survey” – https://ui.adsabs.harvard.edu/abs/1994ApJS…95..419D/abstract
George Helou and collegues [ https://ui.adsabs.harvard.edu/abs/1988iras….7…..H/abstract ] studied the infrared radiation source IRAS 21168+5948 which coordinates coincide with the CO emission region, as just introduced within Avedisova Star Formation regions Catalogue; cfr. Avedisova V. S., 2002 “A Catalog of Star-Forming Regions in the Galaxy” in Astronomy Reports, vol.46 n.3: 193 – 205.
Within Sh2-129 center, recording in Oiii narrowband, is possible to enhance the vision of Ou4 nebula, whose form gave the name of squid nebula.
Discovered in 2011 by French astro-imager Nicolas Outters, the Squid Nebula’s alluring bipolar shape is distinguished by the telltale blue-green emission from doubly ionized oxygen atoms. Though apparently completely surrounded by hydrogen emission region Sh2-129, the true distance and nature of the Ou4 have been difficult to determine.
Recent investigation suggests Ou4 really does lie within Sh2-129 some 2,300 light-years away. Consistent with that scenario, Ou4 would represent a spectacular outflow driven by HR8119, a triple system of hot, massive stars seen near the center of the nebula.
The truly giant Squid Nebula would physically be nearly 50 light-years across.
This work is the result of personal SHO records using William Optics Redcat 51 and ASI1600mm Pro under Bortle 6 sky in Livorno – Italy (home balcony) with integration of records focused about Oiii signal obtained by Takahashi FSQ-106EDX4 and Proline FLI PL16083 camera retrieved from Telescopelive.
Data framelists set available:
here for WO51,
and here for Takahashi106
PixInSight cored workflow for generate 2 distinguished single channel SHO masters, linear-fit by Takahashi Oiii master, each pair blended by pixelmath within final S H and O masters, channel-combined in the SHO integration.
Normal narrowband workflow post-proccessing followed ‘till reaching an SHO starless
and SHO stars separated masters.
The same workflows I took for RGB channels, with the focus on star – separated from starless final integration to be used for final image composing.
I then integrated in Photoshop by screen blending mode after necessary fixing and adjustements.
Parallely, the same workflow I made for Oiii master, using Oiii starless for enhancing Ou4 structure, luminosity and tones, in Photoshop by adjustements and colorizing filtered layer.
Integration of Oiii starless channel within SHO master enhanced luminosity, saturation and structure of Ou4 whole nebula.
