Ngc 4731

[marc4darkskies]

My first image in nearly 3 years ... happy chappie again! :cool::clap::party:

NGC 4731 is not a particularly glamorous galaxy because it's so small (6.7 x 4.1 arc minutes) and lacks lots of colourful Ha blobs to enhance. Consequently, it's rarely imaged. It was a good and reasonably challenging first light target though. I reckon it's quite a pretty little thing though!

It's 65 million light years away and is a member of the Virgo cluster. The small galaxy to the lower left is an irregular galaxy designated NGC 4731A. There is also a galaxy out of frame (the giant elliptical NGC 4697) that has gravitationally distorted NGC 4731. Naturally, there are also a myriad tiny distant galaxies in the full frame.

This is a 15.3 hour LLsRGB (Luminance, synthetic luminance, red, green and blue) exposure.

Full Res crop HERE (https://pbase.com/gailmarc/image/170728469/original)

Full Frame to swim around in HERE (https://pbase.com/gailmarc/image/170666070/original)

Note: in the full frame there are a couple bright stars outside the FOV at the top right of centre that left some artefacts

[strongmanmike]

I'll have one of these too :party:...welcome back on board Marcus, look forward to the results of what will surely be your now endless retirement imaging sessions from your very own dark sky backyard :D

Yes, a bit of a lack luster galaxy I guess :confuse3: but every galaxy has it's interesting aspects and the perfect S shape here is definitely intriguing and you have done it justice none the less :thumbsup:.

After your two-three year move/life transformation, must be good to know everything works properly again too...including you! :lol:

Mike

[Andy01]

That's onw funky shaped galaxy! :eyepop:
Well done & welcome back! :thumbsup::thumbsup::thumbsup:

[codemonkey]

Nice one Marcus!

I imaged this one a few years ago myself and recall it being a difficult target. You've done better with it than I did (not that I set the bar particularly high). I still think it's a pretty cool target if for no other reason than it's unusual shape.

[Placidus]

That's a gorgeous galaxy, beautifully photographed and processed. A wonderful return to action! Bravo!

[Bart]

Unusual shape, nice image.

[gregbradley]

That is a super image Marcus. Getting such a sharp image of such a small and dim object is very difficult and you have shown you have lost none of your maestro self.

Greg.

[Retrograde]

Wow what an amazing looking galaxy - very cool capture Marcus & congratulations on getting back to imaging. :thumbsup:

[DJT]

Love it. lack lustre? Naah, really very interesting given the distortion etc.

Very nicely done and as everyone says, welcome back.

David

[ChrisV]

That's one interesting galaxy. Beautifully done!

[multiweb]

Beautiful narrow field with great colors and details. It's alive again. :thumbsup::thumbsup::thumbsup:

[marc4darkskies]

Thanks Mike. Yes indeed - everything still worked, although my processing skills were a bit rusty.



Thanks Andy!



Oh come now Lee - you're setting the bar pretty high these days - your recent images are excellent! Thanks mate.



Thanks M&T! Or is that perhaps just M ... or maybe T? :question: :P



Thanks Bart.



Cheers Greg! You're too kind! The seeing for the Lum was poor - 2.7 arcsec FWHM. Decon got it down to 2 though. The RGB was much better averaging betweem 1.6 and 2.1 arcsec FWHM hence why I used it for synthetic Lum.



Thanks Pete - yeah , it kind of grows on you doesn't it! :)



Thanks Dave - good to be back. Hopefully down here I'll get more clear nights than I did in Sydney!! :prey:



Thanks Chris - yes it is. Truth of the matter is all galaxies are interesting even if they're not so glamorous. In the end, with some careful processing, they're all beautiful.



Cheers Marc!

[PeterSEllis]

Hi Marc,
You shot inspired me to have a go at this one, for me it is not an easy shot from light polluted Suburbia. Very interesting seeing a galaxy being pulled apart by its neighbor, good ol gravity at work.
Well done.

Peter

[markas]

Not bad for an unglamorous galaxy:D
Great image!


Mark

[marc4darkskies]

Thanks Peter Go for it mate! It'll be interesting to see how you go!



Thanks very much Mark.

[marc4darkskies]

What the heck happened to the weather! :mad2: I'm supposed to be sitting here processing another image but the cloud doesn't seem to be giving me a break! According to CFN my next clear-ish night (for a few hours at least) might be thursday! After that who knows! :sadeyes:

Soooo ... I'm relegated to fiddle-farting around.

I applied Synthetic Lum (Ls) when processing the first time to improve s/n (provided the RGB data is of a similar FWHM to the Lum). I did this within CCDStack (as a mean combine) and it significantly reduced background noise and brought out a few more fainter stars. But, since the seeing was much better for the RGB data (FWHM 2.0 vs 2.7 for the Lum), I could also use Ls to naturally improve sharpness. This can't be done very effectively in CCDStack because averaging blurry with sharp only slightly improves sharpness. Because my processing skills have rusted, I forgot to apply the improved resolution of Ls to the high signal parts of the frame in PS. I've now done this for a noticeable (to me) improvement in sharpness. The brightness profile changed a bit too - for the better.

I've updated my PBase images (https://pbase.com/gailmarc/ngc_4731) but to clearly illustrate the difference, below is a before (left) and after (right) comparison.

[h0ughy]

I can see the changes and looks good. Glad the image acquisition is working for you now. For the weather conditions well someone must be responsible, it was their fault.

You certainly haven't lost your touch

[astronobob]

Yeah, wow, and a new target i havent seen; what an eye-catching pair, 2 spiked stars look good in there too.. .

Keool

[multiweb]

That repro looks great. You got some extra details in there. :thumbsup:

[marc4darkskies]

Thanks a lot guys. I thought it was christmas finding extra detail! :)

It'd be nice to compare it to something though - I crave validation :lol:. But nothing much shows up when googling that's better than mine or comes from a super dooper pro obs. :shrug: I stuck closely to what the colour data was telling me (with modest enhancement), so I'm confident I got the colours right ..... I think.

[gregbradley]

A nice gain in the repro image.

Greg.

[marc4darkskies]

Thanks Greg!

I sated my desire to compare mine vs a large scope. I (re)discovered CHART32 and it has the best rendition out there. I nailed the colours IMO but of course theirs is far superior to mine in terms of resolution and depth. That's hardly surprising, but I think I've made a decent show of it. Reduced scale comparison below. Mine is on the left :lol:

[gregbradley]

An interesting comparison. Considering you're not on an exotic high mountain top and you don't have a 3 metre mirror or whatever they have you've held the comparison quite well.

Greg.

[lazjen]

Not a bad comeback image. Pretty good comparison to the CHART32 too.

[marc4darkskies]

Thanks Greg & Chris.

I don't normally do a comparison like this because it's somewhat akin to masochism :lol:. But I usually like to get some validation on the fidelity of my colour processing and I was so chuffed to see how close I was I just had to share :D

[Slawomir]

A great image, I really enjoyed browsing around the full frame version. And welcome back Marcus :hi:

[marc4darkskies]

Thanks very much Suavi! Yes, the background galaxies, especially when they're partially resolved, are as interesting as the subject! I don't know how many there are in the frame, but there are lots! :)

[topheart]

Great to have a new image from you Marcus!
Awesome!
Cheers,
Tim

[marc4darkskies]

Much appreciated! Thank you Tim!