ASTRO:
     type=Emission nebula
     mag=7.2
     const=Cassiopeia
     dist=7500 ly
     size=325 ly
IMAGE:
     location=EB Driveway
     BrtlCls=4
     moon=9% WnCr
     exposure=CMOS OSC, 50x300s (4.2h), G100
     palette=HOO
EQUIPMENT:
​     optics=ES102CF APO / Starizona "L" 0.65x rdcr, FL(eff.)=464mm, f(eff.)/4.55
     camera=ZWO ASI2600MC-Pro
     filter=Optolong L-eXtreme duo NB
     mount=Celestron AVX
     guiding=Orion 60x240mm, ZWO ASi224MC
SOFTWARE:
     acquisition=Stellarium, APT, PHD2
     processing=PixInsight  (RCAstro), Photoshop (Lumenzia, APF-R), LrC

IC1805, the "Heart Nebula", also known as Sharpless 2-190 (or Sh2-190) and sometimes the older and lesser-known common name of the "Running dog" nebula: is appx 7500 light years away from Earth, located in the Perseus Arm of our home galaxy, the Milky Way, in the constellation Cassiopeia.  Discovered by William Herschel on November 3, 1787, it is an emission nebula with glowing ionized hydrogen gas and dark dust lanes.

The brightest part of the nebula (the "knot" in the upper left corner of this image) is separately classified as NGC 896, because it was the first part discovered.  The nebula's intense red-light output and its morphology are driven by radiation emanating from a small group of stars near the nebula's center.  It is an open cluster of stars in the "Heart of the Heart" catalogued with its own designation as Melotte 15 (or Mel15).  That cluster contains a large number of stars, many of which are only a fraction of our Sun's mass; but, there are a few bright, hot stars that are each nearly 50 times more massive than our Sun.  See a closer view of Mel15 in this collection as, "211113 - Melotte 15 inside the "Heart" nebula".

The shape of the nebula is driven by stellar winds from the larger, hot, more massive stars in the Mel15 cluster.  From our perspective here on Earth the nebula is large, spanning almost 2° (arc-degrees) across the sky.  That's covering an area appx four times the apparent diameter of our full Moon. 

This image was captured with a One-Shot Color ("OSC") CMOS dedicated astro-camera, with a dual narrow band filter centered on the Hα and OIII wavelengths of light.  The image is presented here in the "HOO" color palette.  OIII shows up as a light blue color, while Hα is bright red.

241001 - IC1805 "Heart" nebula