Catalina, AZ, December 6-9, 2023

IC 443 (also known as the Jellyfish Nebula and Sharpless 248 (Sh2-248)) is a galactic supernova remnant (SNR) in the constellation Gemini.  It is about 5,000 light years from Earth.  IC 443 may be the remains of a supernova that occurred, with much uncertainty, 3,000 - 30,000 years ago.  The same supernova event likely created the neutron star CXOU J061705.3+222127, the collapsed remnant of the stellar core.  IC 443 is one of the best-studied cases of supernova remnants interacting with surrounding molecular clouds.  Another older supernova remnant can be seen in the center of the image; the ~100,000 year old SNR, G189.6+3.3.  Shock waves are moving from the lower center towards the upper center of the frame. (Wikipedia)

Per my 8 year old grandson’s preference, this first rendition combined Hydrogen-alpha with Sulfur-II in the red channel, and Oxygen-III in the green and blue channels to create a false color image.  RGB stars were added to the stretched starless nebula.  The sulfur emission is quite strong and overlaps much of the Ha, so the SHO Hubble pallet colors need quite a bit of manipulation to make an appealing image.

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: 0 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 36 subframes (360 min), Gain 100, Offset 32, 1x1 binning
Oxygen-III  10 min x 36 subframes (360 min), Gain 100, Offset 32, 1x1 binning
Sulfur-II.     10 min x 30 subframes (300 min), Gain 100, Offset 32, 1x1 binning
Red             1 min x 93 subframes (93 min), Gain 100, Offset 32, 1x1 binning
Green          1 min x 106 subframes (106 min), Gain 100, Offset 32, 1x1 binning
Blue            1 min x 92 subframes (92min), Gain 100, Offset 32, 1x1 binning

Total integration time: 21.85 hours