Celestial hemisphere:  Southern  ·  Constellation: Ophiuchus (Oph)  ·  Contains:  13 Oph)  ·  13 zet Oph  ·  Khan  ·  Sh2-27  ·  The star Saik (ζ Oph

Image of the day 05/12/2023

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    Runaway Star Zeta Ophiuchi in Sh2-27 - The Dragon's Eye, Timothy Martin
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    Runaway Star Zeta Ophiuchi in Sh2-27 - The Dragon's Eye

    Image of the day 05/12/2023

    Getting plate-solving status, please wait...
      Runaway Star Zeta Ophiuchi in Sh2-27 - The Dragon's Eye, Timothy Martin
      Powered byPixInsight

      Runaway Star Zeta Ophiuchi in Sh2-27 - The Dragon's Eye

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      Here's a closeup of the magnitude 2.56 star Zeta Ophiuchi (ζ Oph) in the Sh2-27 nebula. The Sh2-27 region is one I found quite by accident surfing through the HIPS-to-FITS sky survey in NINA. I was looking for an obscure target to shoot that didn't have any labels in that survey. It's part of a series of shots in this region I've been pursuing under the working title FAAFO—"F^%$ Around and Find Out." A more detailed plate solve of Sh2-27 reveals dozens of LBN and LDN objects within it. But its lack of a higher profile seems to mean that amateurs are not particularly interested in it, which is a shame. It's a fabulous area to shoot.

      As I researched the area further, I became aware of this little gem—a runaway star speeding away from its point of origin at almost a million miles an hour, thus creating a cool-looking bow shock as it ploughs through the gas and dust of Sh2-27. ζ Oph is 20X as massive as the sun, 9X its size, and an astonishing 58,000X brighter. If not for the fact that Sh2-27's dust and gas surrounds it, this would be one of the two or three brightest stars in the sky. It's rotating once a day, which is almost enough to cause it to start coming apart. It would eventually leave the galaxy, but it will blow itself up in a Type II supernova long before that happens. Then who knows what will happen with the dead husk that is left behind (likely a neutron star)? The conjecture is that this star's tightly orbiting, more massive binary companion died in a Type II supernova explosion first. The ensuing loss of mass from the companion slung ζ Oph into the galaxy at large at high speed.

      As far as I know, there are zero closeups of this object here on Astrobin, so as best I can tell, this is at least a quasi-debut object on Astrobin—in terms of being shot at a longer focal length. As such, I've taken the liberty of naming it the "Dragon's Eye." I wanted to call it the "Eye of Dark Brandon," but my wife talked me out of it. 

      Any shots of ζ Oph I can find here are in wide angles incidental to shots of Sh2-27. The vast majority of those are very wide angles adjunct to the Blue Horsehead or Rho Oph. I think I've now seen every Rho Oph shot on Astrobin—more than 800 of them. I'm just thankful that ζ Oph doesn't appear anywhere in Don't Stop Believin' by Journey. If I ever have to hear that song again, my globular clusters will fall off. And if I had to hear it 800+ times, my head would Type Ia.

      I shot a bunch of S2 for this image but wound up not using it. It didn't contribute much, so I left this as HOO. I've also not found many closeups on the web, and none of the ones I found were taken in visible light. They're only infrared or x-ray shots, the most iconic being one from the Spitzer Space Telescope (https://www.nasa.gov/mission_pages/WISE/multimedia/gallery/pia13455.html). They may be out there somewhere, but I can't find them.

      I do understand that this image has a big problem--the double diffraction halo, primarily in the O3 band--around the star. As best I can tell from researching that issue, reflections between the bottom of the O3 filter and the micro-lenses on the ASI6200MM's sensor are the cause. The same occurs in the Ha band to a far lesser degree. About the only thing I could do about this would be to move the filter wheel farther from the sensor. Shorter subs might also help. The former really isn't an option given the constraints of my image train and the likelihood that moving the filter wheel would cause significant vignetting. I do, however, intend to try the latter solution at some point. On the other hand, I think that in this particular case, the halos add to the aesthetic appeal and mystery of this shot. A happy accident, as Bob Ross would say.

      This is a watershed image for me. It's the last narrowband image my Celestron will ever take. I'm converting it to visual and planetary use here at home and replacing it with a Planewave CDK12.5 that will be hosted at Deep Sky West near Santa Fe. So no more deep sky from the OTA we affectionately called "Daddy Scope." Here's a little video I prepared for his retirement party last Saturday night:

      https://www.youtube.com/watch?v=6p_rY6UpeZc

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