NGC7822 - Cederblad 214
NGC 7822 is a young star forming complex in the constellation of Cepheus. The complex encompasses the emission region designated Sharpless 171, and the young cluster of stars named Berkeley 59. The complex is believed to be some 3000 light years distant, with the younger components aged no more than a few million years. The complex also includes one of the hottest stars discovered within 1 kpc of the Sun, namely BD+66 1673, which is an eclipsing binary system consisting of an O5V that exhibits a surface temperature of nearly 45000 K and a luminosity ~100000 times that of the Sun. The star is one of the primary sources illuminating the nebula and shaping the complex's famed pillar of creation - type formations. https://www.swagastro.com/ngc7822.html

Young Cluster Berkeley 59: Properties, Evolution, and Star Formation
Panwar, Neelam; Pandey, A. K.; Samal, Manash R.; Battinelli, Paolo; Ogura, K. ; Ojha, D. K.; Chen, W. P.; Singh, H. P.
Abstract
"Berkeley 59 is a nearby (∼1 kpc) young cluster associated with the Sh2-171 H II region. We present deep optical observations of the central ∼2.5 × 2.5 pc2 area of the cluster, obtained with the 3.58 m Telescopio Nazionale Galileo...Using the near-infrared and optical colors of the low-mass PMS members, we derive a global extinction of A V = 4 mag and a mean age of ∼1.8 Myr, respectively, for the cluster"..."The dynamical status of the cluster suggests that the mass segregation is likely primordial. The age distribution of the PMS sources reveals that the younger sources appear to concentrate close to the inner region compared to the outer region of the cluster, a phenomenon possibly linked to the time evolution of star-forming clouds"..."Comparing the properties of Berkeley 59 with other young clusters, we suggest it resembles more closely the Trapezium cluster."  https://ui.adsabs.harvard.edu/abs/2018AJ....155...44P/abstract

Sh 2-171
Coordinates: (118.41°, 4.68°)
This expanding shell of gas and dust was created by the original star cluster at the heart of the Cep OB4 association, which has now dispersed. It is now lit and ionized by the young star cluster Berkeley 59 (forming the bright nebula called Cederblad 214) and it is expanding into the fainter diffuse nebula NGC 7822. Berkeley 59 is surrounded by another dark region of disturbed gas and dust containing the radio source W1.
Avedisova lists 4 O-stars that ionise this nebula. The hottest of these is the O7 V BD +66 1675. She places Sh 2-171 in star formation region SFR 118.41+4.68 with 46 components, including 3 masers, 14 infrared sources and the dark nebula LDN 1271.
A 2008 study adds a fifth ionising O-star to Berkeley 59, hotter than than any of the ones Avedisova identified. Spectographic analysis reveals that BD +66 1673 has a class of O5 V((f))n. The same study concludes that Berkeley 59 is 2 million years old. A second 2008 study agrees on the age and comments that Berkeley 59 has nine ionising stars in total (classes O-B3). http://galaxymap.org/cat/view/sharpless/171

Cep OB4
..."Blaha and Humphreys identifies 4 O-stars in the OB association Cep OB4, the easternmost major star formation region in the Cepheus clouds. Kharchenko adds a fifth. A 1977 study suggests the presence of a sixth O-star. At least two of these O-stars (DM +66 1674 (O9.5 V) and DM +66 1675 (O7 V)) are located in the ionising cluster Berkeley 59. Kharchenko gives a distance estimate of 1000 parsecs and an age of 6.3 million years for Berkeley 59. A detailed study of the region estimates a distance of 850 parsecs.
The HII region Sh 2-171 is the expanding shell of gas and dust created by the original star cluster at the heart of Cep OB4, which has now dispersed. It is now lit and ionized by Berkeley 59 at its south end, and it is expanding into the dark nebula NGC 7822 at its north end. Berkeley 59 also generates the W1 radio source.
SIMBAD identifies Sh 2-171 with a supernova remnant, SNR 118.3+04.8. Although it was once believed that W1 was energised by a supernova remnant, no such remnant is contained in the April 2006 version of Green's list."  http://galaxymap.org/drupal/node/105

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During the months of July, August and September 2022 Maurizio conducted a series of sessions in our backyard and in a mountainous area to this wonderful nebula.

Our telescope is unable to encompass the entire extent of the nebula and the so-called Little Rosette Nebula-Sh2 170, which has given the popular name Question Mark Nebula to this formation. For that we would need to make at least four mosaic panels...and we are not ready for that type of work yet.

The L-Pro, Extreme and Quad Triad Ultra filters were used. However, the session with L-Extreme was discarded due to the new framing that Maurizio adopted with the Triad Ultra filter to better focus the main region of the nebula.

With the L-Pro, the normal stack was made in DSS to obtain the star base and a stack session made in Triad Ulta's DSS was added, which turned out to be very good and clear. A blend of both stacks was made in Ps to obtain the star base. As an additional note in the image of only stars in CamRaw I apply 12% of 'Moire Reduction' and 'Defringe' that stars sometimes present. I also apply a noise reduction of 15 details 30 noise, and increase their color with the 'Match Color-Color Intensity' tool that enhances the natural color shown by the stars and applying about 3 points of the Luminance with the same tool.

A normal stack of the entire Triad series was made in DSS and Siril. Then in Siril the extraction of Ha and [OIII] was carried out.

GraExpert was applied to Ha and [OIII] in a linear manner. Then HT and GHT were applied with Siril. A starless version of each was also made, the spikes of remaining stars were cleaned, mild Noise Exterminator and mild Denoise Topáz AI were applied.

In Ps, the combination of Ha and [OIII] (H-HO-O) was carried out where the synthetic green channel was composed of 20% Ha and 80% [OIII].

The color of the channels were not placed at the extremes of red or blue or green when the initial combination was made, it gave slightly softer tones.

Then, on the image resulting from the combination in Ps, 'Selective color' was used and the desired colors were enhanced by combining cyan, magenta and yellow. In CamRaw it was given clarity, White and a touch of Dehize. Four layer stamps were made of that combination: a strong S curve was applied to one; 'Smart sharp' was applied to another and 'Unsharp mask' was applied to the third. A layer mask was attached to these layers and the surface and areas that were desired with more definition were highlighted. Each layer contributed around 33% of what was applied to the fourth layer stamp base.

To this combination another layer of clean starless Ha was added and treated with a slight S curve, Noise Exterminator and Denoise Topaz AI as luminosity. The normal stack made in DSS and Siril was also incorporated in small percentages. Then the stars were added.

The original full-frame image was cropped to better highlight its center. It probably would have been ideal to make a stronger crop but it is a shame to leave aside the columns and serpentine shapes of the dust around the central area, which is impressive and we love it.

This nebula not only reflects its complexity and shows impressive areas that make it certainly special for promoting the birth of stars. In its open cluster Berkeley 54, which resides in the image towards the top right but in the center of the image, there is a true nest of nascent stars like in Orion's Trapezium. We take the existence of stars for granted, but the truth is that the areas that create them must have special and unique characteristics and conditions for them to form. Here we also find pillars, gases and dust that intertwine and form extraordinary figures.

This image opens our repertoire for this new year and we hope it will be full of adventures and special moments for everyone to continue capturing the wonders of the universe.

Thank you for visiting us and wish to everyone have Clear Skies.

Processed Dec 2023-January 2024

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