Ngc 253

[codemonkey]

A mere 4.2hrs at 0.5"/px, only 25% of which was L, but this galaxy doesn't need much... that said, could do with a longer integration.

Almost didn't photograph this because I thought it might be a bit too big for my tiny sensor, but it didn't turn out feeling as claustrophobic as I thought.

Full res / capture details here (https://www.astrobin.com/422447)

Edit: New new new new version, now with just over 20hrs of data

[RobF]

Always time to check out a nice NGC 253 image.
Those 2 bright stars always add some nice decoration too in a Newt.

Nice one Lee.

[Atmos]

There is some great fine details within the galaxy Lee, I can see where that 1.8" seeing helped :thumbsup:

[gregbradley]

Wow, that's a ripper image.

Greg.

[Ryderscope]

Not to claustrophobic at all Lee. Shows up the mottled detail of the dust lanes in the spiral arms and brings out the nice colours in the core as well :thumbsup:

[Paul Haese]

Nice image Lee. Great colour, detail and star shapes. It looks great. Always a great galaxy to image.

[multiweb]

Another corker Lee. Love the image scale you get with that rig. :thumbsup::thumbsup::thumbsup:

[ozstronomer]

Nice image Lee, plenty of detail and nice tight stars :thumbsup:

Geoff

[codemonkey]

Thanks very much guys, appreciate the feedback :-)

I decided to tweak it a bit, probably some good and some bad in that, but hopefully a net win. Might get some more data on it next weekend if the forecast holds up.

[Placidus]

Superb! You can see the Galactic Fountain thingy happening beautifully, as if we were there.

[ChrisV]

Very nice and very sharp.

[RobF]

Really like V2 - really lifts it nicely....!

[dave_galera]

No more to say but absolutely superb!

[codemonkey]

Thanks very much guys :-)

Now that some time has passed I'm not as happy with this as I was initially... definitely needs a lot more data and a reprocess. I'm on leave next week and the forecast is looking promising, so fingers crossed I get some decent seeing so I can do better on this one.

[PeterSEllis]

Hi lee,
That's a very nice image, you can be proud of that one.

Cheers
Peter

[codemonkey]

Thanks very much Peter :-)

Had some good skies here lately; good seeing, dark. Had one mishap where for some reason I ended up with 4hrs of really sharp data containing only the tip of the galaxy, but last night everything came together.

I've now got this up to 9.8hrs and have reprocessed it. Still not sure on the colour, but I think it's better. Might revisit the processing again, but I think I'm done with acquisition and plan to move on to other targets.

[gregbradley]

Looking overall superb. A fine minor points. I would concentrate at this point on trying to sharpen up the data. It looks like it could be sharpened more with the right techniques.

The star colours are slightly oversaturated. I personally like the colours you have in the galaxy but the stars look a bit candy.

I would only concentrate on getting extra luminance and working with that layer to sharpen it up as much as you can before artifacts start to appear.

I remember ages ago when I was first starting out one prominent member here (who stopped posting years ago for some reason) did a super sharp Eta Carina image on a 12.5 inch RCOS. He showed how much unsharp mask he could apply with increasingly longer exposure times. By the time he got to 16 hours he could get it really sharp. A valuable lesson.

Greg.

[Atmos]

It's come together really well Lee, very well done :thumbsup:

[strongmanmike]

Fabulous image Lee, I tend to agree with Greg about the colours but otherwise it looks great, well done, enjoyed the view :thumbsup:.

I was up in far North QLD last week, 3hrs drive west of Cairns, under dry Bortle 1 skies with a 24" F4.2 Dob (The Milky Way cast an obvious shadow and the Gegenshein and the rarely seen faint zodical bridge were easy to see all night) and this mighty galaxy looked absolutely incredible and almost blindingly bright, the detail in the disc was like a 5min Luminance sub through say, an 8" scope? :eyepop:..I looked hard but couldn't convince myself of being able to see the faint perpendicular dust streams that rise from the middle 50% of the disc, and visible in your shot, but a number of star knots and dust lanes were quite noticable as was the barred spiral like shape. The central atar in the Ring Nebula was visible without averted vision and I comfortably tracked down several 16.5mag galaxies in Aquarius using the Argo Navis and could have gone fainter but didn't have any fainter references :doh: ...needless to say, t'was an incredible 3 clear nights of viewing!! :prey2:



I believe that would have been one Brad Moore and his remarkable keyhole image :thumbsup: was taken with his new 12.5 RCOS, it featured on APOD back in early 2006 I think?...and to this day is still a benchmark amateur image of the Keyhole really :thumbsup: he also did a deep and detailed wider field Tarantula too, over 30hrs if I recall...not a common practice back then :eyepop: he had just got a new PME and I think was waiting for his RCOS so whacked a small Tak or something on it in the meantime :thumbsup:

Mike

[codemonkey]

Thanks Greg, solid advice there. I've had another look at the final image after reading your comment and noticed that it looks a bit softer than the luminance data would suggest. The luminance data was 1.9" FWHM integrated, which is pretty good, but I'm imaging at 0.5"/px so I'm a bit oversampled still, which will make it look a bit softer... that said, 1.9" integrated is still pretty damned sharp.

I think I know the cause... I've deconvolved the luminance data and then combined it with some pretty noisy, lower quality RGB data and then turned the saturation to 11. I think that's resulted in the image looking softer than it should (because the chrominance data was softer). Based on that, I'm changing my plans for tonight and intend to invest more time in this target, specifically aiming to beef up the chrominance data. I might also try deconvolving the chrominance data. Will be interesting to see what difference it makes.



Thanks Colin :-) Looks like I'm not done with this one yet afterall.

[codemonkey]

Thanks Mike :-) Had noticed you'd been a bit quiet. Sounds like you had a great time. I've hardly even looked through a scope... I had a quick look at the moon with my first scope (Skywatched BD ED80) but that's about it. Posts like yours almost make me want to buy an eyepiece or two...

[strongmanmike]

I do enjoy visual observing and have a reasonably good knowledge of the night sky (worked in a public observatory for over 10 years ;)). It is more tangible than imaging and allows real connection with the night sky and Universe in general, gives your imaging more relevance I recon :thumbsup:...do try it :)

Mike

[gregbradley]

Yes, that's right it was Brad Moore. I think he went on to work for iTelescope or similar.

Greg.

[codemonkey]

Got some more data (bringing it to a hair over 20hrs, which is my longest integration ever) and reprocessed it. I think the colour is way better now.

[strongmanmike]

It's perhaps a little blue for some?.. but I like it a little blue :)

An excellent NGC 253 Lee, well done :thumbsup:

Mike

[codemonkey]

Thanks Mike :-)

I sometimes find that I spend a while processing an image, it looks good but then I go back to it a few days later and think my god, what did I do? Maybe this will be one of those times. Maybe not :shrug: You say it's too blue; do you think it needs more green, or more red, or both? Or do you mean to say it's too saturated, as opposed to the colour balance being off?

I've made a pretty subtle colour adjustment, pulling the blue back very slightly. I think it's an improvement.

[strongmanmike]

I was thinking more red but as I said I like it as it is too :thumbsup:

A past NGC 253 of mine was a top 5 finalist in the ROG APOTY and it was very blue (https://www.flickr.com/photos/strongman/8749856291/in/dateposted-public/) :eyepop: I would process it differently now, so who knows :shrug: as long as it still looks good and yours does :thumbsup:

Mike

[codemonkey]

Thanks again :-) I've boosted the red a touch now, which I think is better too.

[Geoff45]

Nice rendition Lee. Up there with the best.
As an aside, I was interested to see the difference between the high res image on Astrobin and the one with the tech details. There is a double star on the upper edge of the galaxy which provides a good gauge of detail. It’s clear on the high res image but pretty blurry on the low res one.

Geoff

[vlazg]

For only 4.2 hours that is a great result, lots of faint fuzzies in the background as well, more time would really bring them out

[codemonkey]

Thanks very much Geoff :-)



Thanks George :-) This image now has just over 20hrs of data; I've updated the original post to reflect that. Seeing has deteriorated here the last few days and if that's an indication of what's to come over the next few days, I think it's a waste of time getting more luminance. I think I have enough RGB so I'm calling it done on the acquisition on this one. I could probably bring out the faint fuzzies better by lightening the background a bit... I've never been particularly great at bringing out the faint stuff.