M106 badly framed, + experimental binning

[Tommohawk]

Wasn't aware that the edge on galaxy on the right (NGC4226 I think) would come out so well -  Stellarium doesnt give it an image, where it does for the smaller NGC4248. Otherwise I would have made more effort to keep it in the frame - also I'm dithering now and keep forgetting this can lose some of the edges.

I thought I'd give binning a go for the RGB -  never tried this before but I wanted to try and do the whole thing in one night.  So did the B and the R binned first which have slightly different focus, then set NINA to run overnight doing G binned followed by LUM 1x1 which has common focus. Really getting to like NINA, its great for this sort of thing!

What caught me out is I didn't realise that binned images need there own flats and darks, and I'd already stripped down when I realised this. I could re-do the darks in the fridge I suppose, cos I'm not going to get down to -20 otherwise. I tried using unbinned flats on the binned images and I dont think that worked -  lots of vignetting. However, the LP tool in Astrpixelprocessor fixed that quite nicely.

So PDS200 (in need of collimation) with SW 0.9xCC, ASI1600mm @-20, 100 x 60s LUM, 161/76/75 x 30s R/G/B binned 2x2, processed in APP and PS.

Any comment welcomed, thanks for looking.

[tooth_dr]

There is a lot of detail, great job on the processing!  It possibly has a slight magenta cast to it?

NGC4217 is the big edge on galaxy on the right side at the corner.  NGC4226 is the little one at 8 o’clock relative to NGC4217

[michael.h.f.wilkinson]

Apart from the magenta cast, it is really nice and detailed.

[Tommohawk]

4 minutes ago, tooth_dr said:

There is a lot of detail, great job on the processing!  It possibly has a slight magenta cast to it?

NGC4217 is the big edge on galaxy on the right side at the corner.  NGC4226 is the little one at 8 o’clock relative to NGC4217

Thanks! I was quite pleased with it and youre likely correct about the magenta cast. I fiddled with the colour to try and bring out some "gold" but probably got it wrong - my colour vision isnt great! I'm sure I had some Astro tools for PS for sorting gold and magenta but cant find it!

Thanks for sorting the galaxy numbers too - I got them muddled!

[Tommohawk]

2 minutes ago, michael.h.f.wilkinson said:

Apart from the magenta cast, it is really nice and detailed.

Thanks - I was pleased with the detail given the limited time. Started about 10.15pm and had to chuck everything after 3.15 am!

Ok I need to sort the magenta! Any ideas on best method?

[michael.h.f.wilkinson]

Just now, Tommohawk said:

Thanks - I was pleased with the detail given the limited time. Started about 10.15pm and had to chuck everything after 3.15 am!

Ok I need to sort the magenta! Any ideas on best method?

There are various colour balancing tools. I often just use "Calibrate Star Colours" in APP, and then perhaps subtle tweaks using curves in GIMP.

[Tommohawk]

11 minutes ago, michael.h.f.wilkinson said:

I often just use "Calibrate Star Colours" in APP,

Is it just the star colours that are off then? Or does this calibrate everything?

[Nick Smith]

Hi Tom

Great detail in the image.  I adjusted the Hue/Saturation in Photoshop.  Is this more like the colour you were going for?

 

 

Edited May 22, 2020 by Nick Smith
typo

[michael.h.f.wilkinson]

28 minutes ago, Tommohawk said:

Is it just the star colours that are off then? Or does this calibrate everything?

Basically, this uses the known distribution of the colours of stars to adjust the colours of the whole image. 

[Tommohawk]

15 minutes ago, Nick Smith said:

Is this more like the colour you were going for?

Possibly! Like I say my colour vision isnt 100%. 

Is it just the galaxy that's magenta or all of it?

 

[Tommohawk]

Just now, michael.h.f.wilkinson said:

Basically, this uses the known distribution of the colours of stars to adjust the colours of the whole image. 

OK thats fine. Presumably you have to combine RGB in APP for this to work?  Does it adjust individual RGB images or output a single corrected RGB image?

 

[michael.h.f.wilkinson]

1 minute ago, Tommohawk said:

OK thats fine. Presumably you have to combine RGB in APP for this to work?  Does it adjust individual RGB images or output a single corrected RGB image?

 

So far I have mainly worked with OSC cameras, but in the rare cases I captured separate L, R, G, and B captures, I did everything in APP (apart from a little postprocessing in GIMP). 

 

[Tommohawk]

Nice glob! 

I have tried combining LRGB in APP and I really cant get on with it. Just had another go and still not really sure whats going on!

Hmmm - I just tried some final tweaks in PS and it crashed! It does this sometimes when I use colour picker to check the background colour. So now I've lost my history! 

Anyhow I think the problem is that I always check the background colour with the droplet picker thingy cos otherwise it often ends up red - which I dont see well. In this case red lacked a bit so I boosted that  in low tones and also the blue more widely - so maybe thats why magenta. 

Anyhow going cross eyed now so leaving it for a while!!

Still not clear BTW where the magenta is? Galaxy? Whole thing?

[tomato]

Nice detail on a tricky subject.

I tried doing darks by putting the camera in the fridge, but at -30 C the camera put out too much heat and just warmed up (as well as the interior of the fridge!).

[Nick Smith]

2 hours ago, Tommohawk said:

Possibly! Like I say my colour vision isnt 100%. 

Is it just the galaxy that's magenta or all of it?

 

Basically all of it,  Can you see the difference in colour between your original image and the one I posted?

[Tommohawk]

10 hours ago, Nick Smith said:

Basically all of it,  Can you see the difference in colour between your original image and the one I posted?

I can see the difference in the galaxy, but not so much in the background. I think the problem is that I had way more red subs but not necessarily better subs so the Red is stronger. I added some blue to try and balance the galaxy colour and I think this has caused the magenta effect. I have redone this and tried to rebalance the background and desaturate the BG. Hopefully this is better - but I think all the fiddling has let some noise in so I'll quit now! Here's the redo:

[Tommohawk]

12 hours ago, tomato said:

Nice detail on a tricky subject.

I tried doing darks by putting the camera in the fridge, but at -30 C the camera put out too much heat and just warmed up (as well as the interior of the fridge!).

Yeah I did some darks in the fridge before and it worked.... but not sure what it defrosted!