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
NGC2070 Tarantula Nebula in Dorado, JWST NIRCAM raw data
After processing James Webb Space Telescope raw calibrated .fit data focused about NGC2070 by Photoshop screen colorized blending layers, with colours assigned according to NIRCAM filters guideline (cfr.: https://jwst-docs.stsci.edu/jwst-near-infrared-camera ) I was able to obtain this preliminary result.
Integration of NIRCAM f090W, f187N, f200W, f335M and f444W filters
According to spectrum values indicated by NIRCAM filters guidelines I decided a different approach for postproduction, considering the lowest nm values as “blue” colour band, the middle nm values as green, and the highest nm as red channel for an RGB combination.
Using Pixelmath I thus combined in PixInSight f090W and f187N masters creating my blue channel, f200W and f335N as the green channel, and f444W master for red channel.
Being NIRCAM data results of very narrowband recordings, I approach such masters as a peculiar SHO integration, and decided to attempt a starless integration for nebula details and colours work, and final recomposition of starry image using star luminance layer.
Starless version of each master I obtained by PixInSight > Starnet2. Each master I then stretched and export as .tiff in Photoshop for contrast adjustement, star residual removing and hot pixels fixing.
In Photoshop I imported each master into pertinent RGB channel. Then I provide to contrast, saturation and Brightness adjustement layers and fix other pixels problem emerged from channels combination.
Starry NIRCAM f444W filter master as luminance was finally imported as upper layer in luminosity blending mode, while starless f444W master for starless version.
James Webb Space Telescope NIRCam NGC2070 “Tarantula Nebula” , filters f090W, f187N, f200W, f335M and f444W
Photoshop screen blending mode and colorizing layers of f090W, f187N, f200W, f335M, f444W master calibrated RAW .fit data of James Webb Space Telescope NIRCAM mosaic photo session focused on NGC 2070.
After and according to Warren Keller intro and divulgation paper focused about James Webb Space Telescope raw data availability from MAST Portal, archive named after Barbara Mikulski fulls of tons and tons of data including Hubble Space Telescope’s .fits calibrated frames, I’ve downloaded a couple of sets focused on NGC 3132 and NGC 3324 to begin an attempt of post-processing.
Browsing mast portal is kinda experience within a state of art information retrieval system: filters options permits to produce precise queries for matching desired set of data.
JWST target session produce .zip archives tagged, among other criteria, by NIRCAM, MIRI and NIRSPEC instrument label.
suggestions and guidelines about JWST raw data elaboration and post production, most convenient and useful data for an Astrophotographic approach come from NIRCAM sensors and filters.
NIR camera JWST official documentation guidelines specifies and classifies the following filters wheels clusters:
and resumes microns wavelength of filters set as pictured below :
Wavelength and filters label specification, assigned to visible spectrum compass, as confirmed by Keller and Carver tributes, suggests and permits two approach as attempt of post-production and elaboration of JWST NIRCam available data:
a “simplified” RGB or LRGB image integration by channel combination
a “more complex” image integration by available channel combination
An RGB or LRGB approach is “simple” as it consists essentially in identifying proper NIRCAM filter most representative data for RGB channels and integrate them by simple melting channel combination in – for instance – PixInSight: Process > Channel Management > Combination.
NGC 3324 NIRCAM filters available data are f090W, f187N, f200W, f335M, f444W and MIRI f770W, f1130W, f1280W, f1800W.
MAST portal retrieved data for NGC3324 filter by JWST mission
Letting MIRI data to further investigation, I focused on NIRCAM range records download them all.
Each .zip archives exploded out as follow:
file of interest is the _i2d.fits file, generally speaking the biggest among all records.
Opening it in PixInSight generate 8 preview:
A quick autostretch easily let us identify the proper image which I always found as the first, thus the downer pop-up opened.
In the name of .fits file are indicated which filter belongs to, thus it’s very easy to select.
Among JWST data from NIRCAM records focus about NGC 3324 I thought the lowest and more representative for blue channel could be f090W, whilst f444W for red and middle f335M for green.
Before channel combination I did proceed for a star registration of the whole masters, choosing f444W as reference.
I thus integrated all registered frames in percentile clipping and saved the .xifs integration as luminance.
“Simple” [L]RGB is about to end by:
RGB final integration by Process > Channel Management > Channel Combination
LRGB final integration by Process > All Process > LRGB Combination
About more “complex” 6 channel integration I just stretched very lightly by manual Histogram Transformation and export each filter master registered file as .tiff.
Using luminance as bg layer, I thus imported as layer each filter, according to Carver tutorial in screen mode blending with 50% opacity, by adjustment layer/saturation colorizing and boosting/decreasing saturation and luminance trying to respect NIRCAM wavelenght filters charts; take care to change Image > Mode to RGB from greyscale as very first step after luminance opening in Photoshop.
Finally applying an adjustment/curves layers to each filter and retouching pertinent saturation I try to obtain the most balance and well colored images, imho absolutely subjective pov.
