M81 (Galaxies are hard to process!)

[assouptro]

Hi pixel peepers! 

 I’ve spent the last few weeks putting together my “Galaxy Season” rig for some close up work on some familiar targets 

My rig consists of an old Meade 12” lx200 coupled with a Starizona LF reducer/flattener, giving me a focal length of 2084 and a f ratio of 6.8

A modified Meade zeroshift focuser with the motor replaced by a Pegasus Astro focus cube keeps the focus under control

A newly introduced deep sky dad rotator allows consistent framing

A tsoag9 with a zwo helical focuser and 220mm mini guiding the rig snug in front of a QHY CFW3 containing 2” Antlia LRGB V Pro broadband and SHO edge4.5nm filters connected to my QHY 268m that I am still getting to know all balanced on a skywatcher eq8 that is behaving really well since I threatened it with replacement by buying a second hand Mesu! 

Being in a suburban area I generally Image in Narrowband so I’m not skilled when it comes to broadband acquisition and processing 

I feel like a novice, starting out again! 
 

This project has tested me, I’ve had to learn how to get my rotator to not only work with Nina but share it’s position with PhD2 which took some research 

I have had a weird conflict between my Pegasus Astro UPBv1 and a new (to me) Pegasus Astro focus cube v2, I have to have the focus cube disconnected when connecting my laptop to the UPBv1 or my laptop cannot see it! I have reached out to Pegasus Astro and so far they haven’t been able to help me so I just have to make sure I disconnect the focus cube before connecting to the switch?!

 
I am also now using the advanced sequencer in Nina so I can take advantage of features such as centre after drift which is awesome! 
 

Anyway, we had a couple of clear nights during and just after the last full moon and this gave me the time to sort out some issues and start collecting data

I experimented with a few sub lengths, gain/mode etc and settled for mode 1 gain 56 offset 26, 60s broadband and 180s ha 

Processing has been hard… you get into a pattern with processing, using the same tools make them familiar but a galaxy has such a wide range of brightness from the core to the outer edges it’s a tricky balancing act. I have loads of respect for people producing awesome Galaxy shots, it’s not easy! 
 

This is my best attempt so far 

It’s a mix of 2 versions, one stacked in WBPP the other in APP consisting of  roughly 2 hours each LRGB and 4 hours ha (I need more LRGB) 

One with a tamed core 

 

one with a brighter core

 

Sorry for the long post 

Thank you if you read it, it’s a solitary pursuit and there aren’t many people who would understand let alone care about the hurdles involved

Thanks for looking and any pointers would be greatly appreciated 

Bryan 😊

[vlaiv]

Very nice, but I think you have much more data in the image than it shows.

You could bin the data as it is over sampled to help with SNR, but that is a side note - look at this bit:

That is Holmberg IX - irregular dwarf galaxy that is satellite galaxy of M81 - it is there in the data but can't be readily noticed in the image the way it's been processed.

[Gfamily]

21 minutes ago, vlaiv said:

That is Holmberg IX - irregular dwarf galaxy that is satellite galaxy of M81 - it is there in the data but can't be readily noticed in the image the way it's been processed.

My favourite dwarf galaxy - the age profile of its stellar population indicates that it's about 200 million years old - less than one orbit of the Solar System around the galaxy - and incidentally, means there were already mammals on Earth when it formed.  

I wonder if it's formed from material disrupted from the interaction between M81 and M82. 

[assouptro]

1 hour ago, vlaiv said:

Very nice, but I think you have much more data in the image than it shows.

You could bin the data as it is over sampled to help with SNR, but that is a side note - look at this bit:

That is Holmberg IX - irregular dwarf galaxy that is satellite galaxy of M81 - it is there in the data but can't be readily noticed in the image the way it's been processed.

Thanks Vlaiv I appreciate the input

i was aware there was a lot more in the data, I am just struggling to eek it out with my current skill set 

I could bin, I often do at this scale, I would normally use image j on the individual channels before registration and stacking, would binning the stacked masters be as effective or do I need to start again at a base level for the best results? 
 

Thanks again 

Bryan 😊

[vlaiv]

5 minutes ago, assouptro said:

would binning the stacked masters be as effective or do I need to start again at a base level for the best results? 

I think that difference would be small if any, so you can simply bin the masters for simplicity.

[ONIKKINEN]

M81 is a tricky galaxy to process with how bright the core is and how faint the extended outer parts are, i have processed my last year's image at least a dozen times but still dont think i got what i wanted.

Some kind of HDR process is necessary to have both the faint parts and core visible, but still this is a nice image.

[tomato]

Great images, the Ha regions in the spiral arms are spectacular.

[Clarkey]

I think it is a really good rendition. Different with the exaggerated Ha - but in a good way. I particularly like the first one.

[assouptro]

5 hours ago, ONIKKINEN said:

M81 is a tricky galaxy to process with how bright the core is and how faint the extended outer parts are, i have processed my last year's image at least a dozen times but still dont think i got what i wanted.

Some kind of HDR process is necessary to have both the faint parts and core visible, but still this is a nice image.

Thank you ONIKKINEN I understand your frustration!

As a first subject for my new rig it has been difficult 

Your comment and compliment are greatly appreciated😊

 Bryan

[assouptro]

6 hours ago, tomato said:

Great images, the Ha regions in the spiral arms are spectacular.

Thanks tomato! 
I ended up with a lot of ha data! 
I also spent some time learning how to introduce that ha into the red and lum channels using pixelmath which helped make it stand out 

really appreciate your input, it makes me smile to know someone else thinks my image is worth a second look 😊

Bryan 

[assouptro]

1 hour ago, Clarkey said:

I think it is a really good rendition. Different with the exaggerated Ha - but in a good way. I particularly like the first one.

Hi Clarkey

Thanks for the comment 

The first one was my favourite when processing but when I started looking at other renditions I saw many with brighter cores and thought maybe I had done the galaxy some injustice by suppressing its visible unfathomable power!? (I over think sometimes?!!) 

Thanks again for the comment 😊

Bryan

 

 

[Rallemikken]

7 hours ago, assouptro said:

I am just struggling to eek it out with my current skill set 

We'll all have to start somewhere. I'm no familiar with any other than DSLR's, but one thing springs to mind: The galaxy as a whole seems transparent. You have those beautiful red regions that I'll never find in such a small target, but the spiral arms lack some depth and content. My guess is that you have lost some of that in focusing on the background, that is, you have clipped the black or lacked in bringing it forward. When you image a target like this there will always be a compromise between a dark, colorless background and the faintest details in the motif. The sky is never pitch black, nor is it colorless.

[assouptro]

8 hours ago, vlaiv said:

I think that difference would be small if any, so you can simply bin the masters for simplicity.

Hi Vlaiv 

I have reviewed the data and binned the stacks 

I have come to the conclusion that there has to be a point where you just have to admit you haven’t earned the right to display certain details, mainly down to the amount of integration time involved 

I don’t think I can improve the main subject whilst revealing more of the delicate background working with my current data and skill set 

I am however encouraged to spend more time capturing photons in this area as I have the start of something! 
 

Thanks for the encouragement! 😊

Bryan