IC443 is a supernova remnant in the constellation Gemini at a distance of about 5.000 ly. The supernova occurred somewhere between 3.000 and 30.000 years ago.

IC443 is also known as the Jellyfish nebula due to it’s shape. The actual size of the nebula is around 70 ly.

The large star on the left near the nebula is η Geminorum, the other bright star is μ Geminorum.
IC444, a small (blue) reflection nebula surrounding the star 12Gem. is just below the center of the image.

The lanes of dark nebulosity are known as LDN 1567 and LDN 1568.

When looking carefully at lower right of the image, you may notice a small somewhat brighter “bubble”, this is Howell-Crisp 1, which is suspected to be a small planetary nebula only to be discovered in 2006. Check the annotated version listed below if you cannot find it.

Previous/older images:

Mar 07, 2011 – ST-8300M (10″ Newt. Mono)

Image data

Object info
Name IC443 – The Jellyfish Nebula
Type Supernova remnant
Constellation Gemini
Right ascension 06h 17m 13s
Declination +22° 31′ 05″
Distance 5.000 ly
Other designations Sh2-248
Image info
Image date Jan. 23, 2017
Light frames 25x 5 min. G&B (each) unbinned, 27x 15 min. 7nm Ha unbinned (R & Luminance)
Total integration 8h 25m
Dark frames 20x
Flat frames 20x p. filter unbinned, created with an A3 size Posterpoweruk flatfield panel
Bias frames 20x
Software used SGPro, PHD2 Guiding, DeepSkyStacker, Registar, Photoshop CS6
Processing Focusing and image acquisition was done using Sequence Generator Pro.
All separate frames were calibrated, aligned and stacked in DeepSkyStacker.
Images were aligned in Registar prior to combining into RGB.
Photoshop CS6 was used for further processing – curves adjustment, levels adjustment, etc.
Noel Carboni’s toolset was used as well (Local Contrast Enhancement, Deep Space Noise Reduction)
Equipment info
Telescope TMB/LOMO 80/480
Corrector Televue 2″ TRF 2008 flattener/reducer (FL: 384mm f/4.8)
Mount Losmandy G-11 Gemini
Camera SBIG ST-8300M
Guide camera Astrolumina ALccd5-II (Mono)
Guide scope Starwave 50mm f/4.1 Guide Scope
Autoguide software PHD2 Guiding
Filters Baader 2″ 7nm Ha, Baader 2″ RGB + IDAS LPS-P2
Location Landgraaf, The Netherlands
Image comments

Imaging conditions were not good.
Cold winter nights, with slight snow cover, no wind and high humidity.

Images taken over 3 nights. Struggling with flats for Ha, current flats seem to make image worse.
Need to check methodology and find a solution to the issue.