IC 443 (Jellyfish Nebula) · Seestar S30 Pro · 2026-04-08

IC 443, nicknamed the Jellyfish Nebula, is a supernova remnant in the constellation Gemini, located near the star Eta Geminorum at the foot of the Twins. Estimates place it roughly 5,000 light-years away (with some studies suggesting closer to 6,000), giving it a true diameter on the order of 70 light-years; the explosion that created it likely occurred tens of thousands of years ago, though age estimates vary widely. The remnant is associated with a neutron star, and its shock front is seen colliding with adjacent molecular clouds, producing the tangled, tentacle-like filaments that give the nebula its name. Both Hα and O III narrowband filters are effective here, revealing the delicate shock-excited filaments against the surrounding star field, with the brighter western arc offering the most photogenic detail for amateur imagers.

[Source: Wikipedia, en.wikipedia.org/wiki/IC_443; constellation-guide.com]

Annotated Image

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Sky Location

The chart above shows where this image sits on the night sky. The yellow outline is its field of view, with the picture itself drawn at its true orientation; north is up and east is left. Click the chart to zoom in, and use "open full resolution" for the full-size chart.

Image Details

PixInsight Processing

1. Image Integration
2. Drizzle Integration
3. Background Neutralization
4. Automatic Background Extraction
5. Dynamic Background Extraction
6. Spectrophotometric Color Calibration
7. NoiseXTerminator (AI denoise)
8. Multiscale Adaptive Stretch

IC 443, nicknamed the Jellyfish Nebula, is a supernova remnant in the constellation Gemini, located near the star Eta Geminorum at the foot of the Twins. Estimates place it roughly 5,000 light-years away (with some studies suggesting closer to 6,000), giving it a true diameter on the order of 70 light-years; the explosion that created it likely occurred tens of thousands of years ago, though age estimates vary widely. The remnant is associated with a neutron star, and its shock front is seen colliding with adjacent molecular clouds, producing the tangled, tentacle-like filaments that give the nebula its name. Both Hα and O III narrowband filters are effective here, revealing the delicate shock-excited filaments against the surrounding star field, with the brighter western arc offering the most photogenic detail for amateur imagers.

[Source: Wikipedia, en.wikipedia.org/wiki/IC_443; constellation-guide.com]

Annotated Image

The annotated version is shown above - click it to zoom. Open the annotated image at full resolution.

Sky Location

The chart above shows where this image sits on the night sky. The yellow outline is its field of view, with the picture itself drawn at its true orientation; north is up and east is left. Click the chart to zoom in, and use "open full resolution" for the full-size chart.

Image Details

PixInsight Processing

1. Image Integration
2. Drizzle Integration
3. Background Neutralization
4. Automatic Background Extraction
5. Dynamic Background Extraction
6. Spectrophotometric Color Calibration
7. NoiseXTerminator (AI denoise)
8. Multiscale Adaptive Stretch