NGC 7331 and Stephan's Quintet

[RSM]

Here is my first go at the WIP file I posted earlier in the week. Quite happy with this, although I think I may have a second go as I think I've clipped some background data. I've been using PI for a while now and I've just bought the new book which is currently in print (Inside Pixinsight). I've not got fully to grips with the linear phase processing yet before the first histogram stretch. The attached image has had most of the processing (noise reduction, sharpening, etc) performed in the non-linear phase. Comments and constructive critique are welcomed as always...

Richard

[peter shah]

Great shot....I had PI for the 30day trial but never really got a chance to use it. I only hear good things about it.

[RSM]

2 hours ago, peter shah said:

Great shot....I had PI for the 30day trial but never really got a chance to use it. I only hear good things about it.

It's quite involved, I've been using a fairly standard set of processing techniques, but the book is really helping me understand and use more of the techniques. As I did't have PS and I also run a Mac (which limits the software i can use), PI has been a great choice for me. Thanks for the feedback.

[PatrickGilliland]

Nice image and FoV - can see the PI processing there though (not sure if that is good or bad  ) i think the colour is a little off not sure if it is blue or yellow that is not quite right.  

PI is great but my advice (I use it a lot) is half whatever anything suggests and less is more.  There is a lot of toys to play with but unnecessary steps should be skipped.  Learn what you need.  Far better to be a masters of x processes than OK at nx processes i have learnt (the hard way!).

Paddy 

[Dark Horizon]

I thought it was a cracking image and to my eye (im colour blind) the colours look great. Well done!

[RSM]

13 hours ago, PatrickGilliland said:

Nice image and FoV - can see the PI processing there though (not sure if that is good or bad  ) i think the colour is a little off not sure if it is blue or yellow that is not quite right.  

PI is great but my advice (I use it a lot) is half whatever anything suggests and less is more.  There is a lot of toys to play with but unnecessary steps should be skipped.  Learn what you need.  Far better to be a masters of x processes than OK at nx processes i have learnt (the hard way!).

Paddy 

That's a very fair point. There is so much you can do in PI, I guess what I'm trying to do is learn as many techniques as I can and then more importantly learn which ones are needed for a specific image, rather than just pile them all on in search of that extra morsel of data!

im going to have another go (or three) at this one using different mixes of workflows and see what happens. It'll keep me happy for a few nights until the next new moon ?  Appreciate the comments. 

[Maximidius]

Love the quintet, I've never imaged these but it has to be on the to do list! Lovely FOV what setup did you use? Nice rich star colours too, once you've had a play, we can look forward to the new iterations, on what is already a fine image. 

[ChrisLX200]

You have retained colour in the galaxies (including the Quintet) so that is a good achievment, but I suspect there is more detail in your data which you have yet to pull out - possibly a masked deconvolution (to protect the stars) would help, but I'm no expert with PI and would use StarTools for that one

ChrisH

[RSM]

6 hours ago, Maximidius said:

Love the quintet, I've never imaged these but it has to be on the to do list! Lovely FOV what setup did you use? Nice rich star colours too, once you've had a play, we can look forward to the new iterations, on what is already a fine image. 

Hi, thanks for the kind comments Maximidius. This was taken with my SW200PDS with a Canon EOS500D. I used a coma corrector for the first time which meant I was able to use the full image without needing any further trimming of the edges to get rid of it. My intention was to create a wide star field view with the two clusters of galaxies set within the wider view, but not to centre on them - almost like the viewer had just come upon them by chance. I've spent a little time this evening following my new PI book and here is the latest version of the image. I've tried to keep the processing a little "softer" as per the good comments from Paddy and I have to say I'm more pleased with this one than the last. I've learned a little about deconvolution and also to reduce noise and calibrate colours before stretching (before I just removed background and then jumped straight into stretching (too keen to see the results of my late nights!!!). This is about 15 hours of exposure time at ISO800. I also applied darks, flats and bias. I did not use my LP filter as I find I tend to lose some of the galaxy colouring and I particularly wanted to keep those colours. Without the LP filter I kept the individual subs to a maximum of 3 minutes (gave me about 25-33% on the histogram readout on my DSLR) and with guiding I managed to get over 300 useable subs over three nights. Hope you like the refined image....

Richard