Catalina, AZ, December 26-29, 2023

The Heart Nebula, also known as the Running dog nebula, IC 1805, and Sharpless 2-190, is an emission nebula about 7500 light years away from Earth.  It is in the Perseus Arm of the Milky Way in the constellation Cassiopeia.  It was discovered by William Herschel in November 1787.  The brightest part of the nebula (a knot at its western edge) is separately classified as NGC 896, because it was the first part of the nebula to be discovered.  This is a part of IC 1795, the Fish Head Nebula in the lower right of the frame.  The nebula’s hydrogen-alpha, Oxygen-III and Sulfur-II emissions are caused by the UV radiation emanating from a small group of stars near the nebula's center (Collinder 26 or Melotte 15) which contains a few bright stars nearly 50 times the mass of the Sun, and many more dim stars that are only a fraction of the Sun's mass.  The shape of the nebula is driven by stellar winds from the hot stars in its core.  IC 1805 spans almost 2 degrees in the sky, covering an area four times that of the diameter of the full moon. (Wikipedia)

The Heart Nebula was not my intended target.  The full moon was preventing imaging in Auriga, Orion and Monoceros where my preferred targets are located.  After two nights of trying to image in these constellations with narrowband filters, I gave up and moved to IC 1805.  I was able to capture enough data over three nights and shot red, green and blue filter subframes on the third night before the moon brightened Cassiopeia.

Imaging details:

Stellarvue SVX102T refractor with 0.74x focal reducer (FL = 528mm, f/5.2)
ZWO large off-axis guider with a ZWO ASI 174MM mini guide camera
Losmandy G11 mount with Gemini 2
ZWO ASI 2600MM Pro cooled monochrome camera (-10C)
Chroma 36mm Hydrogen-alpha, Oxygen-III, Sulfur-II, Red, Green, and Blue filters
Equatorial camera rotation: 90 degrees

Software:    Sequence Generator Pro, ASTAP plate solving, PHD2 guiding, 
    Losmandy Gemini ASCOM mount control and web client interface,
    SharpCap Pro for polar alignment with a Polemaster camera,
    PixInsight 1.8.9-2,
    Photoshop 2024

Hydrogen-a 10 min x 29 subframes (290 min), Gain 100, Offset 32, 1x1 binning
Oxygen-III  10 min x 29 subframes (290 min), Gain 100, Offset 32, 1x1 binning
Sulfur-II      10 min x 26 subframes (260 min), Gain 100, Offset 32, 1x1 binning
Red             1 min x 45 subframes (45 min), Gain 100, Offset 32, 1x1 binning
Green          1 min x 42 subframes (42 min), Gain 100, Offset 32, 1x1 binning
Blue            1 min x 42 subframes (42 min), Gain 100, Offset 32, 1x1 binning

Total integration time: 16.2 hours