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Image of the day 09/14/2022

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    IC 2944, Can You Spot the Chicken Running Through this Nebula?, 



    
        

            John Hayes
    Powered byPixInsight

    IC 2944, Can You Spot the Chicken Running Through this Nebula?

    Image of the day 09/14/2022

    Getting plate-solving status, please wait...
      IC 2944, Can You Spot the Chicken Running Through this Nebula?, 



    
        

            John Hayes
      Powered byPixInsight

      IC 2944, Can You Spot the Chicken Running Through this Nebula?

      Acquisition details

      Dates:
      Feb. 14, 2022 ·  Feb. 17, 2022 ·  Feb. 20, 2022
      Frames:
      Chroma H-alpha 3nm Bandpass 50x50 mm: 48×600(8h) (gain: 25.00) f/6.8 -10°C bin 1×1
      Chroma OIII 3nm Bandpass 50x50 mm: 33×600(5h 30′) (gain: 25.00) f/6.8 -10°C bin 1×1
      Chroma SII 3nm Bandpass 50x50 mm: 52×600(8h 40′) (gain: 25.00) f/6.8 -10°C bin 1×1
      Integration:
      22h 10′
      Darks:
      17
      Flats:
      17
      Bias:
      20
      Avg. Moon age:
      15.58 days
      Avg. Moon phase:
      93.08%
      Mean FWHM:
      1.85

      RA center: 11h38m49s.105

      DEC center: -63°2811.33

      Pixel scale: 0.448 arcsec/pixel

      Orientation: -179.583 degrees

      Field radius: 0.351 degrees

      WCS transformation: thin plate spline

      More info:Open 

      Resolution: 4678x3161

      File size: 8.5 MB

      Data source: Own remote observatory

      Remote source: Observatorio El Sauce

      Description

      IC 2944 from the Caldwell Catalog is also known as the Running Chicken Nebula or the Lambda Centauri Nebula located at a distance of about 6,500 ly.  This is a large emission region that has an apparent magnitude of 4.5, which is quite bright!  It's also big so it's a very popular target for anyone with a scope in the Southern Hemisphere.   If you look carefully, you'll see that this region is full of Bok globules.  These are regions of coalescing dust and gas first observed by Bart Bok in the 1940s. He hypothesized that these globules are where protostars form.  Subsequent observations at long wavelengths have confirmed this hypothesis and it is now thought that a typical globule contains about 10 solar masses of material in a region 1-50 light-years across. Current thinking is that Bok globules most commonly result in the formation of double or multiple-star systems.  Unfortunately, no young stars have been found in the globules shown here.  The image of the main group of globules shown below was lifted from the full resolution data set to maximize detail. It is interesting that the largest globule appears to be translucent, but that may just be an illusion created by the way it is illuminated.



      If you zoom in and look around, you can also find what appear to be a number of potential Herbig-Haro objects.  The image below is from the lower right side of the image.  Herbig-Haro objects are characterized by long stalks of nebulosity associated with newborn stars. and there are a lot of such regions in this image. HH objects form when narrow jets of partially ionized gas ejected by new stars collide at high speed with nearby clouds of gas and dust.




      I took this data last winter (in the northern hemisphere) while I was traveling through S. America and I almost lost it!  When I first installed the 20" in Chile, I was using Google Drive to download data and I had to do it every morning after an imaging run.  While I was traveling, I didn't have much time to fool with it so the data wound up scattered on the local observatory drive, on Google Drive, and on my working USB drive at home.  When I visited the observatory, I tried to transfer files to a local drive that I took with me, but I couldn't get it to mount on the PC so I had to go through all kinds of gyrations to save the data before cleaning out the observatory drive.  Last week, I started scratching my head over what happened to all this data and it took some detective work to find it and consolidate it all in one place.  This is why I set up a backed-up NAS system when I got back home.  Now all of my data automatically goes to a main NAS drive with RAID as it is gathered and then backed up to another identical offsite NAS system.  I don't have to worry about it and it allows me to treat the observatory drive as a buffer that gets cleaned out periodically.  I now consider this kind of data management system to be a critical infrastructure component for any remote observatory.

      I often start out my stories of gathering data for an image with a tale of woe about how the weather didn't cooperate; but, not this time!  The summer weather in Chile throughout last February was quite good with clear steady nights nearly every night.  I collected subs with FWHM values often better than 2".   I gathered 98 subs  in each of the three channels and by setting the threshold at 2", I achieved a yield of between 33% and 50%.  I rarely pay much attention to the altitude of the object and I just let the process rip along all night, which is probably why my yield isn't much higher.  I think that if I was more careful about object altitude, I could become more efficient in getting good data--while spreading my efforts among more objects.  I'll have to give that approach a bit more thought.  In this case, I gathered subs with FWHM down to 1.3" (with a Moffet 2.5 fit) in every channel and the relatively high quality of this data made it a dream to process!

      After combining channels using a straight SHO combination and stretching it, I separated the result into a starless and a star version.  I processed each separately.  For the stars, I simply desaturated the color to eliminate the violet color that you get with a SHO combination.  After processing the nebula image, I recombined the two images by simply adding the stars to the nebula.  That results in stars that take on the hue of the underlying nebula.  To fix that, I simply masked the result using the stars-only image and desaturated the result to produce mostly white stars.  It's not 100% perfect, but as you can see, it works pretty well leaving the stars without halos, colored wings, or other common artifacts that come from removing the violet cast.

      I oriented this image to best show the "Running Chicken".  Wikipedia claims that the name comes from a group of stars that "looks like" a running chicken, but that's not right.  The Chicken shape jumps out of the central nebulosity.  If you look carefully, you'll see the neck and its feathers.  Most images of this object that I see here on AB show the object rotated 180 degrees from this image and I think that the chicken is harder to see with that orientation.  I see it running to the left with its wings part way out.  What do you think?  BTW, zoom in to check out all the detail in this region.  It's pretty interesting.

      I'm always challenged to pick the best color balance and saturation values when processing NB images but I chose to dial it back a little from my usual super-colorful choices.  Hopefully I got it reasonably close this time.  As usual, I welcome questions along with C&C so fire away.

      - John

      Comments

      Revisions

        IC 2944, Can You Spot the Chicken Running Through this Nebula?, 



    
        

            John Hayes
        Original
        IC 2944, Can You Spot the Chicken Running Through this Nebula?, 



    
        

            John Hayes
        B
      • Final
        IC 2944, Can You Spot the Chicken Running Through this Nebula?, 



    
        

            John Hayes
        C

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      IC 2944, Can You Spot the Chicken Running Through this Nebula?, 



    
        

            John Hayes

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