SH2-129 and Ou4 from Bortle8 skies with OSC

Challenge accepted I said 🙂 Imaging SH2-129 from my Austin Texas backyard seemed impossible at first, but it is coming through.


Sh2-129 aka the “flying squid” is a supernovae remnant composed of diffuse OIII gases within the larger “flying bat” nebula that is primarily diffuse red Ha gases. The appropriately named giant or flying squid was not found until 2011 so it’s a recent discovery that many astronomers and photographers are trying to image themselves!


  • Scope: Esprit 120
  • Reducer: Apex .65x Reducer – 545 FL
  • Filter: Triad Pro Quad Filter
  • Camera: 2600MC Pro -5c
  • Acquisition: Dither every sub. Autofocus every 10 subs. Autofocus after meridian flip
  • Integration requirements: CFA Bayer Drizzle

Total integration time as of 9/19/20202 – 256 5-minute frames.

Day 1:

Do I see anything? Is it worth continuing? Moon is still > 50% but time is running out. I took this challenge late in the season and it blows my mind how quick this object is going down the horizon each morning.

But… I see it!!!

It’s super faint, but it’s there! You can “nuke” it in PI to really see the squid in comparison to background. It’s not too late and it’s not a complete waste of time!

Day 2:

Seventy-five more subs at three hundred seconds each. Little less moon, but dust and extremely high humidity and some wind. I integrated this day to see if I see squid still – yup!

Day 3:

Really bad weather only got about twenty usable subs – I may re-process the master without this day or see if LN can make them better.

Day 4:

Got 70 subs – slightly better weather. Moon less impactful. I used 4 days of calibrated frames to make a “four-day integration” – the fuzz of the squid is starting to build contrast and shape!

Day 5:

Best data yet – best seeing. Transparency improved and no moon. Maybe I can use the best sub from here for LN?

Experimenting with stretch

Work in progress

I am not done with processing this. Here is where some light processing after a few days of data has left me. I’m still learning PixInsight and some of the tools to work with what I can. Mostly happy with what I did get considering it is a Bortle 8 sky.

Download SH2-129 Calibrated Stack

Here is a complete stack of SH2-129 for you to experiment with. This data is released under the Creative Commons Attribution license. Feel free to share with friends and family, you just need to link back to this article/source as the official source. That means you can use this data to create your own derivative works if you just link back and credit us.

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

The XISF and FITS have already been stacked and calibrated with flats.

If you wish to experiment with individual calibrated subs, please contact us and we’ll be happy to share them with you!

PixInsight Processing Tips.

Use Dynamic Background Extraction – be sparse and select just areas outside of the main bat nebula and certainly not anywhere near the center where the squid may be.

Be careful with Background Neutralization. The squid has similar OIII bands as a very diffuse cloud in the bottom. Neutralizing this diffuse cloud can neutralize the squid,

Experiment with extracting RGB into separate channels. The Bat is in R primarily while the squid is in G and B channels. You can process those individually and experiment around.

Please share your processing!

I’m opening this data in the hopes we can share our experiences, tools, and techniques to make use of One-Shot Color (OSC) Narrowband data. A lot of people shoot with Mono Filters, and they swear by them – I don’t doubt the capability of that configuration. I’m just excited to be able to help Color imagers get something similar from their setup too.

If you find this one incredibly difficult to process, don’t fret! You can check out our M31 / Andromeda Galaxy data to learn from too!

If you use our data, create your own image, or post your derivative works on astrobin or telescopius or any image sharing site, please let back to us and leave a comment below – we love seeing what readers do with this data!

1 thought on “SH2-129 and Ou4 from Bortle8 skies with OSC”

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top