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Contains:  IC 444, IC 443, The star Propus (ηGem)
Getting plate-solving status, please wait...
Miracle Jellyfish (IC 443), 


            Gary Lopez
Miracle Jellyfish (IC 443)

Miracle Jellyfish (IC 443)

Technical card

Resolution: 4490x3395

Dates:Dec. 10, 2018Dec. 11, 2018Dec. 12, 2018Dec. 18, 2018

Astrodon Ha 3nm-31mm: 202x180" (gain: 139.00) -15C bin 1x1
Astrodon OIII 3nm-31mm: 66x180" (gain: 139.00) -15C bin 1x1
Astrodon SII 3nm-31mm: 117x180" (gain: 139.00) -15C bin 1x1

Integration: 19.2 hours

Darks: ~30

Bias: ~50

Avg. Moon age: 5.44 days

Avg. Moon phase: 31.76%

Bortle Dark-Sky Scale: 5.00 job: 2840470

RA center: 94.551 degrees

DEC center: 22.670 degrees

Pixel scale: 1.414 arcsec/pixel

Orientation: 13.611 degrees

Field radius: 1.105 degrees

Locations: Monterey Pines Observatory, Monterey, California, United States

Data source: Backyard


The data for this image were one of the gifts I received last Christmas. In December there was a three-day stretch of clear weather. Because of equipment malfunctions, I was only able to collect about 9 hours of light sub, not nearly enough for this object. About a week later there was one more clear night and this time everything worked. I enjoyed perfect tracking and focus from horizon to horizon and found 9 more hours of spectacular data on my computer the next morning. It was a bit of a holiday miracle.

This is the third time that I have processed these data. In the previous efforts, I struggled with a perimeter glow, especially in the SII data, and found that I was over processing and loosing object structure. Since those two earlier attempts, I have experimented and finally devised a processing approach that does a reasonable job of cleaning up the perimeter glow without any obvious impact on the signal.

I have posted two version. Version A was composed and processed to emphasize the details of the lattice work of the billowing gas shells, and the 3-D structure via the texture difference between IC 443 and the surrounding nebular clouds. In Version B I attempted to enhance the 3-D effect by reducing the size of the stars and softening the texture of the surrounding nebular cloud even further. What works better for you? Any feedback would be appreciated.



Gary Lopez
License: None (All rights reserved)


  • Final
    Miracle Jellyfish (IC 443), 


            Gary Lopez
  • Miracle Jellyfish (IC 443), 


            Gary Lopez


Reduced size of stars and softened texture of the nebular clouds surrounding IC443.

Sky plot

Sky plot


Miracle Jellyfish (IC 443), 


            Gary Lopez