M101, LHaRGB, 30 hrs integration

[tomato]

So, by hook and by crook I have got this one out to 30 hrs integration, by desperately snatching some recent subs between clouds before astro darkness is lost, and rummaging around in my archive to find a couple of extra hours of less than premium historic data. Image is made up of:

428 x 2 mins of RGB data captured with Esprit 150/IMX571OSC dual rig in Feb 2022.

196 x 2 mins of RGB data captured with Esprit150/QHY268c in April 2024

214 x 2 mins of Lum data captured with Esprit 150/QHY268m in April 2024

61 x 2 mins of Ha data captured with Esprit150/QHY268mono & OSC/NBZ dual band filters in April 2024.

RGB channels were extracted from the combined colour data in PI, then the LHaRGB channels were combined in APP. Processed in PI with the RC suite of tools and finished in APP.

The quest was to try and achieve the same level of depth and detail as displayed in @ONIKKINEN's fabulous 25 hr 8" Newtonian image posted recently. It hasn't made it but it is improving, as indicated by these  crops to show a distant barred spiral galaxy present in the image. Oskari has estimated I need 70+ hrs to get there, I reckon he's right...

Oskari's 25 hr image:

My 18 hr image:

My 30 hr image:

 

 

 

 

 

[DaveS]

Oh my, that's well worth the time and effort expended on it!

[Sunshine]

Amazing work!

[ONIKKINEN]

Pretty significant improvement on that barred spiral between the 18 and 30 hour images. Some extra wispy bits of the messy spiral arms also much better shown in the new one.

Also, 4 cameras (or is it more?), 2 scopes, all those filters, 2 years and getting close to a thousand subs. Quite the ordeal to put the image together and not getting any easier if you keep going so i applaud the effort.

[tomato]

Thanks for the comments, they are much appreciated. Yes, I'm fortunate to a have a lot of nice kit to image with, but I do take some pride in that I'm managing to use it in the damp and grey UK.

[ollypenrice]

I do like an awful lot about this one but have a couple of reservations. Firstly I think that that the Ha has given the whole field a faint pinkish blush. I think Ha is best added to galaxies in a way which does nothing more than open up the HII regions. Here, I sense its presence even in the two bright stars, one to the right of, and one below, the galaxy. Secondly, I think the galaxy is very blue. This was the subject of a long discussion on SGL a few years ago and I was convinced by Vlaiv's argument that spiral arms were getting ever more blue!

I only say this because the image is top drawer and I'm being very picky as a consequence.

Olly

[tomato]

Thanks Olly, for the feedback. I do recall the galaxy colour discussion, and I was a  supporter of the silvery tone school of thought! 
I feel another version coming on…🤔

[tomato]

So, taking on board Olly's suggestions here is another version. The Ha stars data now plays no part in the image and I have attempted to tone down the blue in the spiral arms and go for a more muted silvery hue.

It's definitely has less of a bling factor now and is perhaps more faithful to the 'real' colour of the galaxy?

Edited May 2 by tomato
correct image posted

[WolfieGlos]

7 hours ago, tomato said:

It's definitely has less of a bling factor now and is perhaps more faithful to the 'real' colour of the galaxy?

I'd like to see the thread discussing the colours, I'll have to search for it. Especially given that I raised a thread a year ago asking why I'm not getting enough blue in mine 🤣

Agreed it looks better without the Ha in the stars, and lovely Ha in all of those spirals 👍. To my eye, there's a bit more colour noise in the outer edges of the arms when held side by side. But let's face it, they are both superb images in any case!

[tomato]

Thanks, you are right about the noise, I have an issue with the flats on some of the Lum frames, which I need to address.

This is a link to the galaxy colour discussion, started by Vlaiv, who else?

 

    
 

    

 

     
 
 

[tomato]

One more attempt at this, after taking some improved flat frames for a portion of the Lum data. Unfortunately I have lost the Ha highlights, the channel combination is the same as the others but I don't seem able to pull them out. I think the data has received a bit too much RC treatment, but I'm all tuckered out with this one. I have amassed 60GB of processed files and my head hurts, it's time to give it a rest.

[tomato]

I had a break and had one more go at putting in the Ha. I tried adding it to the red channel and did a LRGB combination, and it seems to be back. That's it now, I promise.