Centaurus A mega-data project 2013-2025 184hrs

[rmuhlack]

By far my deepest image yet, this "mega-data" experiment combines all my NGC5128 data collected (April 2013-May 2025), across multiple telescope and OSC camera configurations - and at 184.6 hours would be one of the longest exposure OSC images published to date (as of June 2025) of this target.

Data sets from each equipment configuration were separately stacked (to create "sub-stacks") using fully calibrated sub-frames. Those "sub-stacks" were then registered to the 200PDS broadband sub-stack, and then broadband/narrowband separately integrated (to created a "stack of sub-stacks" for the broadband or narrowband data as appropriate) using PixInsight PSF Signal weighting and no rejection (as pixel rejection had already been implemented when pre-processing each sub-stack). NB added to BB data using procedure outlined here https://www.youtube.com/watch?v=jJFUZY5p6yQ. Ha and OIII masks created using continuum subtraction method described here https://pixinsight.com/examples/M31-Ha/ (however stars were removed from BB and NB frames to simplify mask creation with pixelmath). Those Ha and OIII masks were used to isolate those emission areas and subsequently boost L and saturation.

Skywatcher 200PDS + QHY294C (Optolong UV-IR) = 309x300sec (July 2024-May 2025), Strathalbyn SA
Skywatcher 200PDS + QHY294C (Optolong L-extreme) = 264x600sec (May 2025), Strathalbyn SA
Sharpstar13028HNT + ZWO ASI294MC Pro (Optolong L-Enhance) = 75x300sec (May 2025), Strathalbyn SA
Sharpstar13028HNT + QHY533C (Optolong L-Enhance) = 392x180sec (April 2023), Strathalbyn SA
Sharpstar13028HNT + QHY533C (Optolong UV-IR) = 167x180sec (April-May 2025), Strathalbyn SA
Sharpstar13028HNT + QHY533C (Optolong UV-IR) = 275x300sec (May 2025), Strathalbyn SA
Celestron 130SLT (modded) + modded/cooled Canon 450D (Astronomik L) = 131x480sec (Feb-March 2015), Strathalbyn SA
Vixen VC200L + modded/cooled Canon 1000D (Astronomik L) = 82x600sec (Feb 2015), Strathalbyn SA
Celestron 130SLT (modded) + modded Canon 1000D (Astronomik L) = 296x180sec (March 2014), Strathalbyn SA
Vixen VC200L + modded Canon 400D (Astronomik L) = 89x300sec + 28x600sec (April 2013), Griffith NSW

Total integration 184.6 hours

Astrobin version here: https://app.astrobin.com/i/cz7nhy

[Pierre_C]

Wow - what an interesting object, Richard.

As a visual observer, I struggle to see anything of this galaxy from my suburban location. Your image shows how much is actually there if you look at it long enough.

[pmrid]

I see your image/s have captured part of the jet stream - an elusive target at best. Well done.

[Crater101]

That's a serious commitment resulting in a seriously good capture! My compliments.

[gregbradley]

A tremendous effort and fabulous image. It shows the value of keeping your archival data.

Greg.

[astronobob]

Woah, thats something else, experiments are way cool, Well done and great result

[graham.hobart]

That is bonkers ! and really cool!!, thanks for sharing

[xiongz]

That's great efforts, thanks for sharing. What are these ripples of lights which would be interesting if confirmed. I tried to combine data together sometimes as I had imaged some targets using various cameras and scopes as I upgraded bit by bit over the years. A lot of times I found that lots of these earlier data weren't very much useful. But again I was only using Photoshop processing them.

John

[rmuhlack]

Thanks to those who have commented for the positive feedback.

Since I started astrophotography back in 2012-2013 this has been one of my all time favourite targets , having been inspired by benchmark deep images of the time including Mike Sidonio's widefield (https://pbase.com/strongmanmike2002/image/97061387) from 2009 and of course Rolf Olsen's iconic 120 hour version (https://www.rolfolsenastrophotography.com/Astrophotography/Centaurus-A-Extreme-Deep-Field/i-mNgSprP/A) from 2014. Rolf in particular has made several updates to his image, most notably his incredible new 321 hour starless version (https://www.rolfolsenastrophotography.com/Astrophotography/Centaurus-A-Extreme-Deep-Field/i-S7R6h5z/A) (where every remaining background light source is either a galaxy or quasar). Earlier this year Rolf gave a presentation to the Astronomical Society of South Australia where he talked us through this project - and this primarily was the inspiration to produce a composite of all my previous data to see what detail I could reveal with some serious integration time, albeit with only OSC camera data.

In response to a couple of comments:



Thanks Peter. The possibility of revealing that (very dim) Ha relativistic jet was one of the goals of this new effort. Its obviously there now in this image, but further time with a narrowband Ha filter and mono camera (and likely some further processing tweaks) would probably be needed from here to show it more clearly.



Thanks Greg, I agree. To be honest I never thought I would be going back to that old DSLR data but here we are. I've recently upgraded my data storage now too (a 4 bay NAS with 4x16TB drives) so that historic data is far more convenient to access now should the need arise.



Thanks John. Those "ripples" are related to the outer shell-like structure of Centaurus A and are definitely real (Rolf's images I linked to above show those structures quite clearly). I'm using PixInsight which has a number of processes that are helpful for teasing out this sort of image detail.

[AstroJason]

Incredible work. Just being able to process all that data from such a wide range of gear into the one image is a tremendous effort! Beautiful result. Love those shells and the jets

[rmuhlack]

Thanks Jason. There were a few minor tweaks to the pre-processing compared to my normal process (mainly about ensuring accurate registration given the various optical trains, each with differing distortion characteristics). Creating sub-stacks, which were then integrated into a final image certainly made things easier than trying to wrangle all those sub-exposures at once.

To reveal the jets I found the continuum subtraction technique (linked in my original post) to be very effective - a process that i'd not used until now. Definitely a technique i'll keep in mind for future projects when looking to incoporate NB data into a broadband image.

[Nortilus]

That is amazing. Well done.

[lazjen]

That's a great image, the ripples are amazing. I wonder how much contribution to the final image was from each stack?

[rmuhlack]

Thanks Josh/Chris



The weighting heavily favoured the more recent data sets, particularly the data collected with the Sharpstar 13028HNT (which operates at f2.8), followed by the data from the 130SLT (which was f5) and then the data from the VC200L (which had such a low weighting it barely contributed at all, but was nonetheless kept in the overall stack for sentimental reasons)

[spinflip]

That is dedication. Well worth it!:)

[h0ughy]

wow, that is a fair crack at it!! fantastic effort and results, i am glad i looked at the full version. AWESOME