ASTRO:
     type=HII emission nebula
     mag=6.5
     const=Casseopeia
     dist=6,500 ly
IMAGE:
     location=Emerald Bay community, Lake Palestine, TX
     BrtlCls=5
     exposure=CMOS OSC; 69x300s (5.8h), G100
     palette=HOO
EQUIPMENT:
​     optics=ES102CF APO / Hyperion 24mmEP (afocal) 1.7x, FL(eff.)=1238mm, f(eff.)/12.1
     camera=ZWO ASI2600MC-Pro
     filter=Optolong L-eXtreme DNB
     mount=Celestron AVX
     guiding=Orion 60x240mm, ZWO ASi224MC
SOFTWARE:
     acquisition=Stellarium, NINA, PHD2
     processing=PixInsight (RCAstro), Photoshop (Lumenzia, WebSharp-Pro), LrC

This cosmic close-up looks deep inside the Soul Nebula.  The dark and brooding dust clouds outlined by bright ridges of glowing gas are cataloged as IC 1871.  About 25 light-years across, this image's telescopic field of view spans the "mouth" region of the Soul nebula, being only a small part of the much larger Heart and Soul nebulae.  (To view the entirety of the "Soul", see 211129 - IC1848 "Soul" nebula in this collection.)  At an estimated distance of 6,500 light-years, the IC 1871 star-forming complex lies within the Perseus spiral arm of the Milky Way, seen in planet Earth's skies toward the constellation Cassiopeia.  Being an example of triggered star formation, the dense star-forming clouds of the nebula are themselves sculpted by intense winds and radiation of the region's massive young stars.

Westerhaut 5 (or "W5"), is a radio source within the nebula, and spans an area of sky equivalent to appx four full moons.  It is also about 6,500 light-years away from Earth, placing it centrally inside IC 1871.  Like other massive star-forming regions such as Orion and Carina, W5 contains large cavities that were carved out by radiation and stellar winds from the region's most massive stars.  According to the theory of triggered star formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars.  Scientists studying the nebula have been able to show that ages of the stars become progressively and systematically younger within closer distances to the center of these cavities.

This color image adopts a color scheme made popular through the use of a Dual-Band filter used in conjunction with a One-Shot Color ("OSC") camera.  Called the "HOO" palette (an abbreviation for, Hydrogen-Oxygen-Oxygen - as they are assigned to the Red, Green & Blue photographic channels respectively), the process yields a beautiful blend of color where hydrogen gas is represented by its characteristic red color, and oxygen by the blue-green color of cyan.  This is a very popular color palette often used by amateur astrophotographers as they capture images of star-forming regions like this one.

251014 - IC1871 "Soul"_closeup