We all grow with our challenges but I merely underestimated this one, really...

After I have seen the first image of “The Squid” and some stunning examples here on Astrobin I thought this one definitely needs to be on my target list. 

After a period of bad weather the skies cleared up for some day’s and I decided it is time to go for it as I was confident that I now know enough about the behavior of my relatively new 10” f/4 Newton. 

Even so, I was aware that my coma corrector isn’t yet at 100% (already above 55,1x mm but still not far enough…) I started my challenge and it was fun to learn a lot about myself, tolerance, processing, guiding, and re-targeting over several nights.

Until now I went for objects that can mostly be taken easily in one night. Yes, I already realized that I should have taken another night on VdB141, but I still like the result. 

The objects I covered with the L-extreme likely produced enough signal to have plenty of Ha and OIII data to work with. However, this time I decided that I wanted to bring “The Squid” into an RGB Image and I will likely post the sequential steps I created during the journey as updates with additional explanations.

The first night I went out I took plenty of time to “properly” frame as the object fits on the APS-C just fine at 1000mm focal length. I was already pondering about a mosaic that will provide more of the surrounding Sh2-129 but first things first, hunt “The Squid”!

After losing some time with framing I took the whole night with 180s subs and took the flats in the morning. Then right away I went into PI and stacked using the process I was used to and was happy with Ha and then … tada … close to nothing in OIII. Using the 2600MC (I will for reasons switch to mono ) the signal is split into G and B and needs to be combined. 

I went for another night and yep after managing to position the target close enough on the registered images from the first night and taking another couple of hours the OIII signal improved, somewhat…

On the third night, I luckily decided to take the RGB image as it has been one of the clearest nights between some clouds and I was under the impression that this should be enough for the base of the project. A completely new challenge was that PCC didn’t work as the APASS catalog does not provide enough stars for calibration, so I used FluXX.

With a quick setup and already managing to get the framing back to the nights before way faster I took another night with the L-extreme for even more OIII (which still isn’t enough). 

Then PixInsight 1.8.8-9 was released with the new CFA split-channel functionality. I took all of my data and reprocessed it and it helped a lot as the channels align way more precisely. So I hand-picked all subs and recombined them accordingly.

I then tried several methods of joining my Ha and OIII signals, which are always mixed together with the OSC, from within PixInsight Pixelmath, CombineChannels up to blending in Photoshop and so on and so forth, and finally it was a mixture of everything I learned and tried until now which brought up this result I was aiming for. Specials thanks to Bart Delsaert, who helped me with the star size in the RGB base. 

Remaining data
RGB: 98 x 120s (3.27 h)
L-extreme: 288 x 180s (14.4 h)

Endless hours on learning PI and Photoshop methods … 


Ladies and gentlemen, welcome … “The Squid”!