NGC 891 and most of Abell 347 (SW 150-PDS)

[geeklee]

I picked up a second hand SW 150-PDS at the start of November and finally had the chance over the last few weeks to show it some clear skies.  At least, it seemed clear but reviewing the sub afterwards showed how mixed conditions were.  From the 9 hours captured, I settled on ~6 hours of subs - the best of a bad bunch!

The framing was inspired by an absolutely superb image by @tomato that was posted recently.  

363 x 60s.  SW 150-PDS and ASI 533MC-Pro.

Processed in PixInsight.  I used BlurXTerminator with lower settings and saw a slight improvement in NGC 891 and a noticeable one in star sizes.  Stars were also blended from two different stretches.  As always, click through for the full size.

Thanks for looking.

 

I spent some extra time on NGC 906 and NGC 914 with their own masks to increase colour and try and bring out a little more structure.

Edited December 23, 2022 by geeklee
Added a Finder Chart.

[Lee_P]

Thanks for sharing, I really like that image. The annotated version is impressive too. 

[simmo39]

Nice!

[geeklee]

Thanks for the comments @Lee_P @simmo39

11 hours ago, Lee_P said:

The annotated version

Definitely a fun part of the workflow, checking annotated views.  Some of those extra galaxies showing are worth spending a bit of time enjoying and sometimes looking up further. 

PGC 9301 in the top right is cool.

..and PGC 9101.

I could go on and on 🤣

 

[tomato]

That’s a cracking image,  not sure if BXT has made a contribution but the detail on the cluster galaxies is excellent.

When I see my subs graded in quality order I always agonise about where to make the cut, so I admire your resolve to leave out a third of your data, but the end result speaks for itself.

Thank you for the kind words.

 

[geeklee]

1 hour ago, tomato said:

That’s a cracking image,  not sure if BXT has made a contribution but the detail on the cluster galaxies is excellent.

Thanks @tomato.  As mentioned I felt BXT did a little work on the galaxies, but more on star sizes (although the finished one also has additional reduction/processing).  Here's a comparison of the original stack (top) with just a simple stretch.  It's had no colour calibration or any other processing.  Below is the crop from the finished image.  I think NoiseXT made more of an impact for me and then using separate masks (using the GAME script) to spend individual time on some of these smaller galaxies.

1 hour ago, tomato said:

When I see my subs graded in quality order I always agonise about where to make the cut

I'm the same.  I remember getting the subs from the second night on the computer and thinking "these are great, much better star sizes than the night before" then instead seeing the star count being about half (or less) what it was the night before with less signal.  Gutted!  You've just got to work with what you can in the UK!

Thanks again.

Edited December 23, 2022 by geeklee

[Lee_P]

2 hours ago, tomato said:

That’s a cracking image,  not sure if BXT has made a contribution but the detail on the cluster galaxies is excellent.

When I see my subs graded in quality order I always agonise about where to make the cut, so I admire your resolve to leave out a third of your data, but the end result speaks for itself.

Thank you for the kind words.

 

This makes me wonder, if BlurXTerminator is good at correcting for issues such as guiding errors, should we be more lenient on the subframes that we allow into our stacks -- or still, as I do, axe data fairly brutally to ensure only high quality ingredients go into the pot? 🤔

[tomato]

APP usually puts eggy stars to the bottom of the pile so they go, but as you say BXT would move them higher up the table. The big issue I have is with subs subtly affected by thin high cloud. On the one hand some detail is missing but I know the software will take care of any gradients they create and each one is another 2 minutes on the total integration time. If all else fails I go with the best 80%....

[geeklee]

Just now, tomato said:

The big issue I have is with subs subtly affected by thin high cloud. On the one hand some detail is missing but I know the software will take care of any gradients they create and each one is another 2 minutes on the total integration time. If all else fails I go with the best 80%....

Yes, this! 

@Lee_P I wish subs affected by guiding was the main issue - it always seems to primarily be sky conditions - thin high cloud etc.  It's only when looking through an entire night (or more) in SubFrameSelector in PI and then visually looking through them (usually in APP in a manual way!) do I see unwelcome patterns and differences.