Around 2000 light-years from Earth is the Flying Bat Nebula (Sh2-129), seen here as a huge cloud of red hydrogen gas. Within this is the glowing blue Squid Nebula (OU4), thought to be a low-mass star near the end of its life, blasting its outer layers off in two opposite directions.
To say this was a tough target would be something of an understatement! The Flying Bat and Squid are notoriously difficult, and to be honest are really only within the purview of astrophotographers blessed with very dark skies and Mono cameras. I found it even trickier than the Shark Nebula. Still, I like a challenge, so tried it with my Askar FRA400 small refractor and ZWO ASI2600MC Pro camera from my city-centre location.
I gathered around 50 hours of data, and used PixInsight’s SubframeSelector tool to whittle this down to the best 28 hours. The pre-processing took my PC almost 24 hours to complete.
Then it was onto the processing. The image was very noisy and ideally I’d have gathered much more data (I’ll explain why I didn’t in a moment), so to help once I’d stretched to non-linear I split the channels into RGB and ran NoiseXTerminator on each of the three.
I could see the red Flying Bat easily enough, but the blue Squid was very difficult to make out. This isn’t surprising as it’s mostly faint OIII. Fun fact: the Squid was only discovered in 2011! My solution was to import those RGB channels into Adobe Lightroom and study them carefully. The Squid wasn’t visible at all in the Red channel (not surprising as that maps to H-alpha). I could just about make it out in the Green channel, and again but even fainter in Blue. I made a few tweaks to those Green and Blue channels to bring the Squid out more, and then recombined the channels in PixInsight before continuing processing. This resulted in the Squid being much easier to see.
The final photo won’t win any awards, but I think it’s interesting because of the conditions under which it was taken: from a city centre using a small refractor and OSC camera. Tackling this target in particular made me want dark skies and a Mono camera, as really they’re needed to do it justice. But I still very much appreciate how simple data acquisition is with OSC. For more on this, check out my article OSC vs Mono from a City.
And as for why I didn’t keep collecting data? I’ve bought a new telescope, so started cannibalising astroimaging components from my Askar FRA400 to move over to the new rig. Stay tuned to Urban Astrophotography for more about this..!
Imaging details
* August 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, Photoshop, Lightroom
* 840 x 120 seconds
Total integration time: 28 hours
By Lee Pullen
Example source data
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