The Jellyfish Nebula was formed around 30,000 years ago, when a high-mass star reached the end of its life and exploded as a supernova. The material that the star was made from — plus new elements forged in the extreme temperatures of the explosion — blasted outwards. Fast-forward to today, and we see the remnants as The Jellyfish Nebula.
Askar 130PHQ: February 2025
My plan for this target was to use a variety of filters in order to capture H-alpha, SII, and OIII wavelengths of light, plus RGB stars. Unfortunately, bad weather and technical issues meant I needed to cut the project short, with just 20 hours of Optolong L-Ultimate data. This gave me enough H-alpha and OIII to create an interesting image though, although I had to apply a lot of noise reduction during processing.
I used a few SetiAstro PixInsight processes, including to stretch the image from non-linear. The trickiest thing was dealing with large halo around the bright star Propus. I used Photoshop’s Generative Fill to remove this. For more details on how I processed the image, scroll down for a full video walkthrough.
Time for some science. We know that The Jellyfish Nebula is the remains of a star that exploded as a supernova; but was anything left of the star? It turns out yes, the dense core was left and became a neutron star. This is a sphere about 20km across (twice the size of my home city of Bristol), but with more mass than the Sun. In terms of density, it’s second only to a black hole.
The pulsar itself is moving through space at a break-neck speed off 800km ever second. The reasons for this aren’t known for sure. The original star could have been careening through space when it went supernova, or perhaps the explosion itself blasted the remains of the star, in effect giving it a cosmic kick!
The pulsar is leaving a trail of high-energy particles in its wake as it hurtles through space. These have been observed by astronomers using the Chandra X-Ray space telescope and Very Large Array radio observatory in New Mexico. (More info here). My telescope and camera can’t detect light in these wavelengths, so the neutron star is invisible to me. Still, I managed to track its location down on my image. It’s a good example of how multi-wavelength astronomy reveals a universe normally hidden from view:
Use the slider below to compare my image with the multi-wavelength professional image.
Imaging details
* 15 January – 28 February 2025 (six weeks)
* Bristol, UK (Bortle 8)
* Telescope: Askar 130PHQ Flatfield Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Mount: Sky-Watcher EQ6-R PRO
* Guide: William Optics 50mm Guidescope with 1.25″ RotoLock; ZWO ASI 120MM Mini
* Control: ASIAIR Plus
* Software: PixInsight, Lightroom
* Filters:
– Optolong L-Ultimate (Ha/OIII): 240 x 5 minutes (20 hours)
Total exposure time: 20 hours
By Lee Pullen
Processing walkthrough
Example source data
Askar FRA400 version 2, reprocessed December 2022
From the Reprocessing Bonanza 2022. This version uses exactly the same data as version 1, but with better processing tools and skills. This was incredibly hard to edit at the time, but a fair bit easier with new tools and skills. I like the colour palette in the original, and the glowing lilac shades in particular, but I’ve never been able to reproduce them! The original image looks terrible when viewed large or with any kind of zoom, however, so I tried to improve that while also keeping some nice colours in.
Askar FRA400 version 1, January 2022
To say I had a tough time processing this would be a bit of an understatement! I made an initial version based on an integration time of 20 hours, and liked the unusual glowing colours I pulled out, but it was very noisy.
The following night was clear, so I collected more data, bringing my total to 24 hours. I then spent the best part of two days trying various processing methods on this version. I could produce final images that were technically better than my original attempt, but just didn’t grab me as much from an aesthetics perspective. In particular, I found it difficult to pull out different colours from the L-eXtreme data, and had to make extensive use of colour masks.
In the end I went back to the original, made a few tweaks, and declared it finished. I’ve still got the freshly integrated 24 hour version though, so may return to it in the future.
* January 2022
* Bristol, UK (Bortle 8)
* Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Filter: Optolong L-eXtreme
* Mount: Orion Sirius EQ-G
* Guide: William Optics 32mm; ZWO ASI 120MM Mini
* Control: ASIAIR Plus, ZWO EAF
* Software: PixInsight, Lightroom, Topaz DeNoise AI
* 600 x 120 seconds
Total integration time: 20 hours
By Lee Pullen
Example source data
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