M81 and M82: Ha and Oiii integration to RGB

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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.

For Rista excellent studies, please cfr. https://jonrista.com/the-astrophotographers-guide/the-zwo-asi1600-guide/the-zwo-asi1600/preliminary-analysis/ and https://www.cloudynights.com/topic/578198-short-exposure-time-asi-1600mm-cool/ both on 02/08/2023.

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

Sh2-132 (LBN 473) in HOO: a deep study of Lion Nebula

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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. 

According to Lynds 1962 Catalogue of Dark Nebulae there are three main dark nebulae classified as LDN 1150, LDN 1154 and LDN 1162; Cfr. https://heasarc.gsfc.nasa.gov/W3Browse/nebula-catalog/ldn.html

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. 

Cfr. Van der Hucht K. A. , 2001 “VizieR Online Data Catalog: 7th Catalog of Galactic Wolf-Rayet stars” in NewAR,45, 135. https://ui.adsabs.harvard.edu/abs/2001yCat.3215….0V/abstract

Hamann W. R., Gräfener G. , Liermann A. , 2006 A&A,70, 205. https://ui.adsabs.harvard.edu/abs/2006A%26A…457.1015H/abstract 

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. 

Avedisova, V. S., A Catalog of Star-Forming Regions in the Galaxy, in Astronomy Reports, vol. 46, n. 3, marzo 2002, pp. 193-205. https://ui.adsabs.harvard.edu/abs/2002ARep…46..193A/abstract

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. 

Cfr. Saurin T. A. , Bica E. , Bonatto C. , 2010 “Star clusters in the Sh2-132 complex: clues about the connection between embedded and open clusters” in journal of Royal Astronomical Society, 407, 133-143 (2010) https://academic.oup.com/mnras/article-pdf/407/1/133/3067396/mnras0407-0133.pdf

Sh2-132 (LBN 473) “Lion Nebula” in SHO

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Crop and Starless

M16 (NGC 6611) and the Pillars of Creation: a James Webb Space Telescope records study

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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) and the Pillars of Creation

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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).

For Cheseaux observation cfr.: http://www.messier.seds.org/xtra/similar/deches.html [18/07/2023]

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]

M20 (NGC 6514) in SHO

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Astrobin: https://www.astrobin.com/8lkg32/

Dettagli d’acquisizione

Date: 16 Giugno 2023

Astrodon H-alpha 3nm 50×50 mm: 6×300″(30′)
Astrodon OIII 3nm 50×50 mm: 4×300″(20′)
Astrodon SII 3nm 50×50 mm: 6×300″(30′)

Integrazione: 1h 20′, giorno lunare medio: 27.92 giorni, fase lunare media: 2.89%

Telescopi O Obiettivi Di Acquisizione: Planewave CDK24

Camere Di Acquisizione: QHYCCD QHY600 Pro M  ×

Montature: Mathis Instruments MI-1000/1250

Filtri: Astrodon H-alpha 3nm 50×50 mm · Astrodon OIII 3nm 50×50 mm · Astrodon SII 3nm 50×50 mm

Software: Adobe Photoshop · Pleiades Astrophoto PixInsight

Annotations by PixInSight

Sh2-129, Ou4 in SHO palette

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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.

Markarian’s chain

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Sh2-188 Firefox Nebula

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M63 (NGC5055) Sunflower galaxy

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Spiral galaxy in the northern constellation of Canes Venatici belonging to M51 Group located to the southeast of the M101 Group and the NGC 5866 Group. The distances to these three groups are similar, thus the M51 Group, the M101 Group, and the NGC 5866 Group are actually considered as part of a large, loose, elongated structure; cfr.: https://arxiv.org/abs/astro-ph/9910501.

In the mid-19th century, Anglo-Irish astronomer Lord Rosse identified spiral structures within the galaxy, making this one of the first galaxies in which such structure was identified.

According to Ann, Ha et Al., 2015 [cfr.: https://arxiv.org/abs/1502.03545] catalogation of visual classified galaxies in local Universe the shape or morphology of this galaxy has a classification of SAbc where SA indicating a spiral form with no central bar feature, and bc describes a moderate to loosely wound arms, as evinced from a visible light observation with general lack of large-scale continuous spiral structure, thus M63 is considered a flocculent galaxy.

According to Thornley, 1996, when observed in the near infrared, a symmetric, two-arm structure is seen and each arm wraps 150° around the galaxy and extends out to 13,000 light-years (4,000 parsecs) from the nucleus; cfr. https://arxiv.org/abs/astro-ph/9607041.

According to Graham, 2008, the existence of a supermassive black hole (SMBH) at the nucleus is uncertain. If it’s true then its mass could be estimated as (8.5±1.9)×108 M☉, in few words around 850 million times the mass of our star the Sun; cfr.: https://arxiv.org/abs/0807.2549

Tully, Courtois and Sorce researches focused on galaxy distances measured M63 at 29.300.000 light years, alias 8.99 megaparsec. Cfr.: https://arxiv.org/abs/1605.01765

In this work I use bundle observation from Telescopelive Spain 2 CCD Officina Stellare 700mm RC.

First, by PixInSight, Cosmetic Correction was required to better recalibrate subframes, especially removing vertical couple of lines. Then the same registration, integration, bg removing, spcc, deconvolution and denoising routine to generate LRGB masterframe, while in parallel, working on Luminance master for final Photoshop image reconstruction, with starless and stars levels blending – respectively in luminosity (L) and screen (Stars) mode.


Framelist available here:

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