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
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.
Sh2-214 and Sh2-215 very faint practically invisible Sh2 spot within Cepheus area; starless master shows both faint nebulosity and a third spot which I wasn’t able to identify.
SH2-157, the Lobster Claw Nebula, is an emission nebula located about 11,000 light-years away in the constellation of Cassiopeia.
According to SHO palette, red/orange and predominantly yellow regions of the nebula evinced a very large H II region while the blue-colored are predominately regions featured by the emission of light from molecular oxygen.
On the top NGC 7635 – the Bubble Nebula, and on the middle the star cluster NGC 7510.
Telescopi O Obiettivi Di Acquisizione: William Optics Redcat 51 Camere Di Acquisizione: ZWO ASI1600MM Pro Montature : Sky-Watcher EQM-35 × Filtri: Astronomik H-alpha CCD 6nm · Astronomik OIII CCD 12nm 1.25″ · Astronomik OIII CCD 6nm · Astronomik SII CCD 6nm Accessori : ZWO ASIAIR Plus · ZWO ASIAIR Pro · ZWO EAF · ZWO EFW 8 x 1.25″ / 31mm Software: Adobe Photoshop · Pleiades Astrophoto PixInsight Telescopi O Obiettivi Di Guida : QHYCCD Mini Guide Scope Camere Di Guida : ZWO ASI120MM Mini
Dettagli d’acquisizione Date: 09 Dicembre 2021 · 11 Dicembre 2021 · 12 Dicembre 2021 · 13 Dicembre 2021 · 15 Dicembre 2021 · 16 Dicembre 2021 · 17 Dicembre 2021 · 18 Dicembre 2021 · 08 Gennaio 2022 · 09 Gennaio 2022 · 10 Gennaio 2022 · 11 Gennaio 2022 · 12 Gennaio 2022 · 13 Gennaio 2022 · 14 Gennaio 2022 · 16 Gennaio 2022 · 18 Gennaio 2022 · 22 Gennaio 2022 · 23 Gennaio 2022 · 24 Gennaio 2022 · 28 Gennaio 2022 · 29 Gennaio 2022 · 31 Gennaio 2022 · 01 Febbraio 2022 · 02 Febbraio 2022 · 05 Febbraio 2022
Pose: Astronomik H-alpha CCD 12nm 1.25″: 79×180″(3h 57′) (gain: 139.00) -20°C bin 1×1 Astronomik OIII CCD 12nm 1.25″: 62×180″(3h 6′) (gain: 139.00) -20°C bin 1×1 Astronomik SII CCD 12nm 1.25″: 77×180″(3h 51′) (gain: 139.00) -20°C bin 1×1 Integrazione: 10h 54′ Dark: 33, Flat: 33, Dark dei flat: 33 Giorno lunare medio: 12.35 giorni Fase lunare media: 58.64% Scala del Cielo Scuro Bortle: 6.00
Reprocessing 2022 records focused about M42 region. In this work there’s a main core in LRGB, background removed, SPColorCalibrated, Deconvoltued and denoised is then integrated and boosted by Ha and Oiii narrowband master (Bgremoved, Deconvoluted and denoised) with Ha applied to L and R channel, Oiii to Green and Blue. Final starless and 0.65 stars pixelmath blended and Photoshop retouches.
