Messier 16 - The Eagle Nebula/The Pillars of Creation, 4.75 hours in SHO

Date: July 10, 2025

Cosgrove’s Cosmos Catalog #0141

First light for both the Sharpstar SCA260 V2 and the Whispering Skies Observatory! (clck for access to full res image via Astrobin.com)

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    Background

    We’ve had a few clear nights, and on one of those, I wanted to do a quick test with my new Sharpstar SCA240 V2 scope on a bright narrowband target. This was seen as a quick test.

    So I collected one night of data on Messier 16 to see how things were looking. It turned out to be both an interesting and challenging image. as you will see….

    About the Target

    Overview

    Messier 16—better known as the Eagle Nebula—is located some 6,500 light-years away in the northern reaches of the constellation Serpens Cauda. What the eye sees as a modest sixth-magnitude patch is actually a large H II region, its hydrogen set aglow by the ultraviolet output of the young open cluster NGC 6611 at its heart. Among the sculpted ridges and voids rise the famous “Pillars of Creation,” three dust columns roughly four to five light-years long that silhouette against the cavity they helped carve. 

    Anatomy of a Stellar Nursery

    Note: NGC 6611 is not shown in my annotated image as the label conflicts with the M16 label. However, NGC 6611 is an open star cluster that can be seen behind and around the M16 label.

    NGC 6611 is barely one to two million years old, yet already hosts dozens of O- and B-type giants whose radiation and stellar winds both erode and ignite the surrounding cloud. At the pillars’ tips lie evaporating gaseous globules (EGGs): dense knots in which protostars continue to accrete even as their cocoons boil away. High-resolution imaging shows shear flows, shock fronts, and infant stars in the infrared that are invisible at optical wavelengths. Models and recent time-lapse analyses suggest the columns will survive another hundred thousand years or so—long by human reckoning, fleeting by galactic standards. 

    A Brief History of Discovery

    Swiss observer Jean-Philippe de Chéseaux first noted the nebula in 1745-46; Charles Messier added it to his catalog in 1764. It remained an obscure binocular object until Hubble’s 1995 Wide Field and Planetary Camera 2 portrait catapulted the “Pillars of Creation” into pop-astronomy fame. Hubble’s 2014 revisit sharpened the view, Herschel and Spitzer pierced the dust in the far-infrared, and in 2022, the James Webb Space Telescope’s NIRCam and MIRI instruments revealed thousands of newborn stars embedded inside the very figures that Hubble made famous. 

    1995 — Hubble WFPC2 (visible-light original)

    Credit: NASA, ESA, STScI, J. Hester & P. Scowen (Arizona State University)

    2014 — Hubble WFC3/UVIS (visible-light high-definition revisit)

    Credit: NASA / ESA / Hubble Heritage Team (STScI/AURA) 

    2022 — JWST NIRCam (near-infrared view)

    Credit: NASA / ESA / CSA / STScI — image processing by J. DePasquale, A. Koekemoer & A. Pagan (STScI)  

    Looking Ahead

    Although the pillars are slowly photo-evaporating, they will continue producing new stars for tens of thousands of years before finally dispersing into the wider Sagittarius spiral arm. From Earth’s vantage point, however, their present-day grandeur is safely “time-locked”: even if a supernova has already shattered the columns, that light will not reach us for many human lifetimes.

    Annotated Image

    Image created with Pixinsight’s ImageSolver and AnnotateImage scripts.

    Location in the Sky

    Findershart created with Pixinsight’s ImageSolver and FinderChart scripts.

    About the Project

    This is actually my third imaging project on the Snew C260 scope. I have not yet documented the second because I was disappointed with the framing I did, which made the project kind of blah. However, I document and share even my failed projects, so I will eventually get this done.

    After having a less-than-thrilling reaction to project number 2, and knowing that the moon was soon to return, I decided to use the night of June 26 to complete this little project.

    It was meant to be a test since I knew I would only get one night of data from it. But I was eager to do a narrowband test and see how the scope did.

    I set up NINA to pursue M16, and the entire night’s sequence ran smoothly with no major issues. Very simple. Very easy.

    The fact that I got 4.75 hours of good data on such a short note shows that things went well!

    Previous Efforts

    First Attempt: I first shot M16 back in August of 2019. It was one of my first images - and it really looks that way! This was shot on my Williams Optics FLT 132mm with an OSC camera with a grand total of 0.3 hours!! See that imaging project HERE.

    Second Attempt: June 2020. Same telescope and camera. 2.6 hours Integration. Much better! See that Project HERE.

    Third Attempt: July of 2021. This was shot with my Astro-Physics 130 platform, in narrowband. 3.9 hours of integration. This is one of my favorite images. This current image has more color and detail, but I still like this one the best! See it HERE.

    My 2019 Effort

    My 2020 effort

    My 2021 effort

    This is the kind of series that an astrophotographer likes to show. A nice progression of images getting better over time.

    This new image is very interesting and very good on several levels. But does it continue the progression? Is it significantly better than the last one? I would say it is different, but not necessarily better.

    Why would this be?

    • Maybe I am just used to the older one and more attached to it

    • I came from my Astro-Pysics scope, which has amazing sharpness and contrast. The new one is with a Super Cassigrain - it is good but the quality of the optics will be different.

    • Maybe the nights I shot the old one were better! It was very hot and humid when the most recent was shot and maybe the skies were just not as transparent.

    Data Capture

    We had a string of 3 clear nights, and on the third night, June 26, I decided to shift targets and do this narrowband test.

    My Flats set up for the SCA260.

    For this project, I used the SharpStar SCA260 V2, pairing it with the ZWO ASI2600MM-Pro through Hα, O III, and S II filters. Over 4.75 total hours of integration.

    Since I was using narrowband filters, I ran the camera with a gain of 100 and an offset of 50.

    Because of the high heat, I used a target cooling temp of -10C. I was able to achieve this temp with some difficulty due ot how warm it was out.

    I used my Off-Axis guider for these exposures.

    All were captured on one night.

    Dark and flats were captured the following night. I found that I have a light leak somewhere in my optical chain, so now I do my darks when it is actually dark out, and this solves the problem.

    My flats were shot using a large LED panel mounted on the wall. I placed fans underneath, pointing up, to keep the bugs off the panel during the Flats Wizard operation.

    Image Processing

    The image processing for this image was more difficult than I expected.

    I followed my normal narrowband workflow which looks like this:

    I used a drizzle 2x process on this to maximize resolution and detail.

    But as I progressed, I realized that I had a problem.

    In the past, I was always reluctant to switch to a pure starless workflow because the tools at the time removed stars but often left residual blemishes from the stars in the starless image. If you then stretched and enhanced the starless data, these blemishes became ugly artifacts. So, what you had to do was to remove the blemishes with a clone tool or something similar.

    However, when RC-Astro released the current generation of StarXTerminator, I was hooked. With StarExterminator, it was rare to see blemishes.

    Star Blemishes Return

    So, I used my normal workflow, and as I reached a decent point with the nonlinear starless image, I did a quick ScreenStars to reunite the starless version with the stars to see how it was progressing.

    At first, it looked great. Then I looked deeper. I saw this:

    Some ugly artifacts around bright stars!

    That’s not good! So I went back to the starless image, assuming the problem was there. It was.

    Definately baked int the nonlinar Starless image.

    So I went back to the nonlinear master SHO image - which looked like this in a few sample spots.

    Sample #1 Before StarXTerminator

    Sample #1 Before StarXterminator

    Noisy, but not horrible-looking stars.

    Then I applied StartXterminator.

    After StarXTerminator.

    After StarXTerminator.

    Faint - but there are definitely residual blemishes from being left by the bright stars.

    Bright stars come out on the SCA260 with diffraction spikes. In general, StarXterminator does a good job with diffraction spikes. But I found that with the SCA260 and narrowband, this was not the case. Even worse, if you are aggressive with BlurXterminator, the starless results look even worse.

    After going nonlinear, adding some sharpening and other enhancements, these blemishes looked much worse.

    So I had to go back to square one.

    I went a lot easier on BlurXterminator and stretches and I got something that looked better in the starless image:

    These are much improved, but they are still there, and they looked bad when you added stars back in.

    So what did I do?

    I ended up exporting the final nonlinear starless images as a 16-bit TIFF file. I imported this in Photoshop and used the healing brush to eliminate them.
    Here is what the image above looked like after this step:

    This is much better. I only did the worst ones. If you look carefully, you can see some faint residuals that I did not bother to fix.

    This produced an acceptable result, but it is not how I want my processing to go.

    I will be contacting RC-Astro and asking for guidance

    A Different Star Issue

    Since I found issues with the Starless images, I got paranoid and really scrunched the stars-only image.

    I found a new issue. This one appears not to be caused by StarXterminator, but rather by an issue in the optics of the SCA260. I saw some ring artifacts around the bright red stars.

    I've heard of these issues being reported by some SCA260 users, but this is the first time I've encountered them here. I found two very bright stars that were warm in color that had this problem.

    The fix?

    Same thing - export to Photoshop, and use the healing brush to touch it up crudely - see the result below:

    Like I said. Crude, but better, as it turns out, I was going to crop the image, so these stars would be lost anyway.

    Other Challenges

    The other issues that I had some difficulty with were tuning the colors and some color discontinuities in the blue.

    The blue region seemed to be a swirling mix of deep blue and cyan. This mix looked a little mottled. This suggested that I needed more integration time to smooth out these details. I was not going to get more integration for this test, so I ended up tuning the blues and greens to create a smoother-looking mix.

    The other issue is one that I have ALL OF THE TIME.

    Being a high-color g-y, I tend to push a bit on saturation and contrast. I probably go too far for many Astrophotographers. So I often second-guess myself when finalizing these positions.

    I like where I came out - but again, this may not be your preference.

    Results

    On one level, the final image did not come out badly given the low integration time, the star blemish issues, and such. However, as I mentioned earlier, I am not sure I prefer this to my previous effort. In fact, I know I don’t.

    So that is a bit disappointing.

    But it was a good test - the image came out not half-bad. And I have a few issues that I need to research further as I learn to work with the SCA260 scope.

    I would love to hear your feedback on this image!


    More Info

    🖼️ Image & Media Resources

    Pillars of Creation — Hubble WFPC2 (1995)

    The iconic visible-light portrait that first revealed the three dust columns to the public.

    🔗 NASA Science 

    Pillars of Creation — Hubble WFC3/UVIS (2014)

    Higher-resolution follow-up showing finer tendrils and photo-evaporation at the pillar tips.

    🔗 ESA/Hubble 

    Pillars of Creation — JWST NIRCam (2022)

    Near-IR view that pierces the dust and exposes hundreds of newborn stars.

    🔗 NASA Webb Mission 

    Pillars of Creation — JWST MIRI (2022)

    Mid-IR image mapping cooler dust and molecular gas—the “skeleton” of future star birth.

    🔗 NASA Webb Mission 

    Eagle Nebula — Chandra X-ray + Hubble Optical Composite

    Combines X-ray point sources with Hubble color data to highlight young stellar activity.

    🔗 Chandra X-ray Center 

    Digitized Sky Survey Wide-Field Mosaic

    A 3.8° × 3.3° DSS2 frame that puts M16 in its Milky Way neighborhood—ideal for scale graphics.

    🔗 ESO/DSS v2 

    🧑‍🔬 Science & Research

    Messier 16 Fact Sheet

    NASA’s summary of distance, size, stellar population, and key Hubble findings.

    🔗 NASA Science 

    Hubble Spies a New “Cosmic Pillar”

    2025 release detailing shock fronts and dust-erosion rates in one of the smaller columns.

    🔗 NASA Science 

    Pillars of Creation: 3-D Multi-wavelength Exploration

    Interactive visualization fusing Hubble, JWST, Spitzer, and Chandra data sets.

    🔗 NASA SVS 

    Star-Birth Clouds in M16 — “EGGs” Up Close

    Explains the evaporating gaseous globules that hide embryonic stars at the pillar tips.

    🔗 NASA Science 

    🔭 Observing & Imaging Guides

    Explore Three Great Summer Nebulae

    Practical advice on spotting M16 (plus M17 & Sh2-54) with binoculars and telescopes.

    🔗 Astronomy Magazine 

    Messier 16 — Eagle Nebula Overview & Finder Tips

    Coordinates, brightness, visual appearance, and best-season guidance for amateurs.

    🔗 Messier-Objects.com 

    Seek the Treasures of the Milky Way

    Includes observing notes on the Pillars and recommended nebula filters for faint detail.

    🔗 Astronomy Magazine 

    📜 History & Catalog Data

    Revisiting an Icon: Hubble Captures the Pillars 20 Years On

    2015 ESA/Hubble release comparing the 1995 and 2014 images and outlining their impact.

    🔗 ESA/Hubble News 

    🗺️ Constellation & Context

    Serpens Constellation Overview

    Background on the constellation’s two-part structure, notable stars, and deep-sky objects.

    🔗 Wikipedia 


    Capture Details

    Lights

    • Number of frames is after bad or questionable frames were culled.

    • 19 x 300 seconds, bin 1x1 @ -10C, gain 100, Astronomiks 36mm diameter 6nm Ha Filter

    • 17 x 300 seconds, bin 1x1 @ -10C, gain, 100, Astronomiks 36mm diameter 6nm O3 Filter

    • 21 x 300 seconds, bin 1x1 @ -10C, gain 100, Astronomiks 36mm diameter 6nm S2 Filter

    • Total of 4 hours 45 minutes

    Cal Frames

    • 30 Darks at 300 seconds, bin 1x1, -10C, gain 100

    • 30 Dark Flats at each Flat exposure times, bin 1x1, -10C, gain 100

    • 15 Ha Flats

    • 15 O3 Flats

    • 15 S2 Flats


    Capture Hardware:

    Click below to see the Telescope Platform version used for this image

    • The Final Version 1.0 Configuration:

      • Scope: Sharpstar SCA260 V2 260mm f/5.0 Special Cassigrain Astrograph

      • Focus Motor: ZWO EAF 5V

      • Guideing: ZWO OAG-L

      • Mount: IOptron CEM70

      • Tripod: Custom Steel Pier with modified IOptron Top Pier Plate

      • Camera: ZWO ASI2600MM-Pro

      • Filter Wheel: ZWO EFW 7 x 36mm - Second Gen

      • Filters: ZWO 36mm ZWO LRGB Gen II, Astronomiks 6nm Ha, OIII,SII

      • Guide Camera: ZWO ASI174MM-Mini

      • Dew Strips: Dew-Not 140 cm Heater strips for Main Scope base

      • Power Dist: Pegasus Astro Pocket Powerbox Micro

      • USB Dist: 12V powered USB Hub

      • Polar Alignment NINA 3-point Method

    • Software:

      • Capture Software: PHD2 Guider, NINA

      • Image Processing: Pixinsight, Photoshop - assisted by Coffee, extensive processing indecision and second-guessing, editor regret and much swearing…..


    Image Processing Detail (Note: This is all mostly based on Pixinsight)


    1. Assess all captures with Blink

    • Light images

      • Ha images:

        • Removed 2 -clouds

      • O3 images:

        • Removed 4 for clouds

      • S2 Images:

        • Removed 2 for clouds

    • Flat Frames

      • no issues seen on individual subs

    • Flat Darks

      • no issues seen

    • Darks

      • no issues seen.

    • Summary:

      • 40 minutes lost to clouds

    2. WBPP Script V 2.8.9

    • Load all files

    • Dark exp tolerance set to zero

    • Light exp tolerance set to zero

    • Pedestal auto for all frames

    • CC auto for all groups

    • Select max quality

    • Ref image set to auto

    • Selected the target folder

    • Drizzle 2x Square set

    • Executed in 33 minutes with no errors

    WBPP setup.

    Post Processing View of WBPP

    WBPP Pipeline view

    3. Import Master images and Rename

    Master images.  Ha, O3, S2

    4. Create and Process the SHO Color Image

    • Create the Master_SHO image using the ChannelCombination Tool

    • This image is all green as expected. Normally, I would run DBE here, but this time I decided to try to get the color in the ballpark and then apply DBE to the color image. To do this, the first thing I did was run the NarrowbandNormalization script. See the panel before for the settings I ended up using.

      • Run NarrowbandNormalization

      • This left a brown looking background and magenta stars, so I wanted to deal with that next,

      • First, the Magenta stars:

        • Invert the image - this makes the magenta stars green, so we can then run SCNR for green

        • Run SCNR for green at 95%

        • Invert the image gain

      • That fixed the stars, so now let’s fix the background

        • Run BackgroundNuetralization - see panel

        • That looks pretty good now.

    • Now let’s run DBE to remove the gradient and nonuniformities seen. This also adjusted the green balance.

    • Note: I think in the future I will continue to run DBE earlier on, as I normally do. I liked the color I had after NarrowbandNormalization and BackgroundNormalization, and the DBE shifted that.

    • Apply BXT on the color image with “Correct Only”

    • Run PFSImage: X = 11.97 Y=9.96. Not sure I believe this as the diffraction spikes might influence things.

    • Apply BXT with full correction. See panel-snap for values used. These were selected after interactive testing.

    • Run NXT = 0.75

    • Run STX to go starless. Preserve the stars

    The initial SHO Image

    After NarrowbandNormalization (click to enarge)

    Narrowbandnormailization Params used.

    Image Inverted. Magenta stars are now green. (click to enlarge)

    SCNR 95% Green run (click to enlarge)

    Image now inverted again - the stars look much better.

    After BackgroundNeutrlalization. (click to enlarge)

    Params used.

    DBE Sample pattern for SHO image. (click to enlarge)

    SHO image before DBE. (click to enlarge)

    SHO image after DBE. (click to enlarge)

    Background image subtracted.  (click to enlarge)

    Star Sizes as determined by PFSIMage. Not sure it handles diffractions spikes correctly.

    BXT settings used. Determined by trial.


    SHO Image Before BXT, After BXT Crorrect Only, After BXT Full Correction, After NXT=0.75


    The Final Linear SHO image before star removal.

    Master_SHO_Stars (click to enlarge)

    Master_SHO_Starless (click to enlarge)

    5. Process the nonlinear SHO Starless Image

    • Use the STF->HT method of going nonlinear

    • Use CT to adjust the overall tone scale and color

    • Use SelectRange to create a range mask that covers the lower exposure background of the image.

    • Apply the mask

      • Use CT to adjust the background to be darker and more neutral

    • Remove the mask

    • Run HDRMT with levels = 6 to open up the highlights a bit

    • Use CT to tweak the image

    • Use ColorSaturation to reduce purple tones and slightly boost blues.

    • At this point, I knew about the residual star blemishes, so I exported the starless image and fixed the blems with Photoshop’s healing brush .

    • Note: I should mention that this a fairly simplified processing that what I typically do. I usually get much more involved in color masks, sharpening, etc. Since this was a test, I simplified this. As a result, I did more active polishing on Photoshop than I normally do.

    Initial SHO Starless Image (click to enlarge)

    RangeMask targeting background (click to enlarge)

    After HDRMT (click to enlarge)

    After CT adjust (click to enlarge)

    Use CT to adjust background. (click to enlarge)

    CT adjust the entire image. (click to enlarge)

     
     

    The final SHO Starless image after ColorSaturation Adjustment.

    Example of residual star blemishes. (click to enlarge)

    After Fixing in Photoshop click to enarge)

    6. Process the SHO Stars-Only Image

    • Use the NarrowbandNormalization tool to fix up stat colors a bit

    • Take the linear star image and make it nonlinear by manually using the histogram tool.

    • Check over the image for any artifacts. Ring Artifacts were found on two bright yellow stars. These were not STX artifacts - these are due to the optics of the SCA260. I have heard other reports of this.

    • Export the star image to Photoshop and due to a crude correction before moving to the next step.

    Starting SHO linear Star Image

    After Adjustment with the NarrowbandNormalization tool.

    Nonlinear Stars using Histogram tool

    One of two ring artifacts found on bright orange stars (click to enlarge)

    After a crude Fix n Photoshop (click to enlarge)

    11. Add the Stars Back

    • Use the StarScreen script to add the stars back in.

    The Final Starless Image. (click to enlarge)

    The Final SHO Stars image. (click to enlarge)

    The ScreenStars script combines the stars and starless images. 

    12. Move to Photoshop and do the final Polish

    • Export as 16-bit TIFF

    • Open in Photoshop

    • Rotate and Crop to create the final composition.

    • Use the Camera Raw filter to tweak color, tone, and Clarity.

    • Use Camera Raw ColorMix to adjust blue tones to darken them

    • Use the Lasso Tool to select the upper right corner and lighten it a bit

    • Use the Lasso Tool to select the lower right corner and lighten it a bit

    • Use the smart sector to grab the blue area

    • Apply a slight Gaussian blur filter to smooth it out a bit.

    • Do a final curve adjustment to make it snappier.

    • Add watermarks

    • Export various versions of the image

    The final image sent to Photoshop for polishing (click to enlarge)

    Lighten the lower right corner. (click to enlarge)

    after a slight guassian blue of the blue area. (click to enlarge)

    Lighten the upper right corner (click to enlarge)

    Smart Select of the blue area (click to enlarge)

    The Final Image after a CT curves adust to make it just a bit snappier.


    Patrick A. Cosgrove

    A retired technology geek leveraging his background and skills in Imaging Systems and Computers to pursue the challenging realm of Astrophotography. This has been a fascinating journey where Art and Technology confront the beauty and scale of a universe that boggles the mind…. It’s all about capturing ancient light - those whispering photons that have traveled long and far….

    https://cosgrovescosmos.com/
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    Sh2-54 - The Serpent Nebula - 8.9 Hours of SHO