[PRejto (Peter)]

Originally Posted by Geoff45

I like the sharp detail Peter and I'm one of those people who likes to see blue in a galaxy. It may be better with the blue slightly toned down. I'll have a go when I'm next at my computer.
Geoff

Originally Posted by Geoff45

Hi Peter
I had another look at your image. The histogram says a lot:
1. All the R, G, B peaks line up perfectly, which indicates good colour balance.
2. There is some room to raise the black point.
3. The histogram peaks are very narrow, indicating that more stretching may be helpful.
Geoff

Thanks very much Goeff! I see what you mean about the narrow peaks. I've subsequently tried to stretch a bit more but I'm paying a very high price with noise. It increases dramatically. I've already pushed noise suppression as far as I'm able to. As for the black point, do you think I've set it too high? I like to leave some room and not have things too dark. My monitor might be misleading me, however.

Originally Posted by gregbradley

I am not a fan of others reprocessing your image for you. Its a bit like someone redoing your painting for you. You are the artist, you make the decisions good or bad. Technical points like too much noise, needs more exposure, stars aren't round are fine. But subjective points like colour and framing and methods of processing are a bit crossing the line in my opinion.
There are so many ways to processing an image that its not really granting the artist and their work any respect by redoing it for them. If you don't like the result that is the area where the audience can say - no, don't like it.

If the artist is a newbie and is after advice and help that's a different story. But that is not the case here.

Your original image is fine and needs nothing.

Greg.

Thanks so much Greg! I think you are right with what you have said. What I posted I have been working on (3 reprocesses) for more than 2 weeks. On the one hand I don't mind seeing what can be done with the same data when starting from scratch and I'malways looking for ways to do better...like most of us I'm sure. Allan has certainly made me think about my reasons and my choices. And, at the end of the day that isn't bad either. So, I don't mind his effort in the whole context. It provoked a most interesting discussion and I've already learned a lot.

Originally Posted by strongmanmike

Not a bad effort there Pete, some nice details visible. Not exactly sure about the colour because as you say what is the right colour? If I go with aesthetics alone I recon combining your result with ReproAl's might give the best of both worlds

Mike

Mike, I have appreciated your comments along the way and any compliment from you is gratefully accepted!! See, look what 2 telescopes can do when they decide to cooperate (for once!!). It "only" took me 13 hours of imaging instead of 26! That's nice considering the weather. With only one scope I wouldn't have this image that's for sure! You are officially "forgiven" now for suggesting this nonsense of putting 2 scopes on one mount!

Originally Posted by Placidus

Hi, Peter,

The sharpness of your stars and galactic detail is quite superb. It speaks for a combination of excellent seeing (over the Pacific Ocean?), together with perfect technique. You've gone quite deep, too.

Regarding colour, I like an image to show the physics of what is going on. Strongly interacting galaxies will have powerful bursts of star formation, and consequently will have regions that are very blue compared with an elliptical galaxy. Also in general the core of a spiral galaxy should be much cooler and therefore less blue than the star-forming regions. Your image shows all those "internal" features.

But what about absolute colour? Should one aim to show the ellipticals and distant, bland, background spirals as a warmer colour to match their known physics, or is it fine to say that they are unimportant and worrying about them is missing the point of the image? I could be persuaded either way.

So a lovely, deep, startlingly sharp image that says a lot about the interacting pair. Really well done.

Best,
Mike

Hi Mike,

You are too kind! Indeed, occassionally the Pacific Ocean produces some unbelievable seeing. Sadly the light pollution extracts a heavy price. The one thing I can say about my observatory is that it is very convenient and has provided the perfect opportunity to learn. I think I've progressed some over the past few years. Many thanks again for your kind words! Now what I really want is a dark site to put my equipment!

Originally Posted by gregbradley

Those comparison images just go to show how far amateur imaging has advanced. Multi million dollar scopes and CCDs sitting on a near perfect mountain top site and its only a bit more detailed than Peters effort.

Wow.

Greg.

I guess it goes to show that we are mostly seeing limited. I had a few exceptionally steady nights. That together with FocusLock allowed me to take full advantage. Perhaps it also shows that with enough imaging time certain disadvantages of light pollution can be dampened down.

Originally Posted by Ryderscope

Fantastic to see what can be produced from the suburbs of Sydney.

Thanks!!! Yes, a worthwhile project.

Originally Posted by Shiraz

I don't think that it's a good idea to have the human eye response built into the imaging system. Then, when you look at the image with your human eyes, you will have applied the human eye response twice. I think that the best bet is to have as flat a response as possible in the imaging system, so that the resulting image will represent the source light distribution with as little spectral distortion from the imager as possible.

On that basis, the 694 would appear to have a distinct advantage and maybe the colours in your lovely image are closer to "right", whatever that means.

Thanks Ray. Of course you are right. Another moment of not thinking the problem all the way through. Your image of NGC1532 is terrific. I notice how similar they are...I see similar star colours, small galaxy colours, outer arms & core. The main difference seems to be in the dust lanes where yours are consistently brown where mine are redder in one area with a kind of purple haze around the dust lanes. I've no idea why there is this difference when so much else is similar. Do you see the 694 chip as "flat" over the visual range? It doesn't look too flat to me, but I suppose it might be so in comparison to other chips. Thanks again for your helpful comments in my initial stages of processing!

Peter