The Trifid Nebula CDK17 REPRO 2!

[gregbradley]

I took this some time ago and only just got around to processing it recently as I catch up on some backlogged images.

CDK17, LRGB, Proline 16803, PME mount.

Crop view:
http://upload.pbase.com/gregbradley/image/153044809/large regular size
http://upload.pbase.com/gregbradley/image/153044809/original large size

Widefield view:
http://www.pbase.com/gregbradley/image/152870200/large regular size
http://www.pbase.com/gregbradley/image/152870200 large size

3 hours plus 1 hour of Ha used for the bright stars in the core.
Greg.

[Rod771]

That's very nice Greg :thumbsup:

Very colourful.

[Peter Ward]

Post processing is very much in the eye of the beholder....

In this case I'm seeing a very high-key image with highlights effectively burnt out.... which is a shame as I suspect the underlying data is all there (and then some ).

A good M20 for sure... but sorry...not one of your best. I think it needs some top end gamma correction.

[IanP]

Peter, I think gamma correction will also affect this gorgeous blue nebulosity. I'd go for HDRM-transformation in PixInsight with only the "to lightness" box checked. It will look absolutely stunning.:hi:

[DavidTrap]

Sorry Greg - have to agree with Peter & Ian.

DT

[Paul Haese]

Good colour Greg. Star shapes look good too and the MMOAG with the ST-i certain has had a positive impact. Looks like the flats are working in this image.

[alpal]

Hi Greg,
It looks like it was good data.
Did you stretch it in 32 bit FITS files from stacks before processing in 16 bit?

(as per my humble advice here:
http://www.iceinspace.com.au/forum/showthread.php?t=113110
)

cheers
Allan

[gregbradley]

Thanks Rod.



Fair enough. I've done a repro using gamma and offset correction plus shadows/highlights tool and its toned down the highlights.



Thanks Ian. I looked for that tool and I couldn't find one called that. I looked some more and I see the HDR Wavelets transformation tool has a lightness checkbox. I tried that but the correction looked a bit savage and damaged the image. No doubt there are ways to finesse this tool. I am fairly new to PI but can use some of it. I have some tutorials paid for I need to sit down and watch and go through it some more. There are some useful tools in there for sure.



Fair enough. I've done a repro as per above and I've toned down the highlights. I think what happened is in the effort to bring up the extensive faint blue nebulosity its brought up the bright areas too much with it.



Yes flats work well on bright objects just the faint galaxies I have trouble with.



Yes thanks for that Allan. I am pretty sure. I'd have to check the workflow but the initial processing I always do is using CCDStack and I think default is 32bits but perhaps its 16. It may be something I need to check in CCDstack to default to 32.

Repro posted to the same links.

Thanks for the feedback.

Greg.

[RickS]

Greg,

A couple of options for making HDRMT more gentle are to explicitly mask the image before processing with HDRMT (I use PixelMath to combine a luminance mask with a star mask so that stars and dim areas are protected) or to use PixelMath to blend the original image with the processed version.

BTW, I was surprised that the stellar jets aren't more clearly visible in your image. Did you have bad seeing?

Cheers,
Rick.

[gregbradley]

Thanks Rick.

It was imaged some time ago. Probably was and why I didn't process it until now.

Greg.

[alpal]

Greg,


Hi Greg,
the repro is much better & I'd be interested to know if it was stretched in 32 bits?
The bright areas are in a narrow range - & so are the dark areas.
It still looks like those areas could be stretched out.
I have found that FITS Liberator does the hard work for you
when used in compression mode & it's free from NASA.
I have used it in compression mode x^1/5 but your image might
work better in x^1/3 or one of many other functions.
It can then be saved as a 16 bit TIFF for processing in Photoshop
or just about any other package.
Also - I don't know whether all the blue on the left hand side is real or not - it could be a partial blue caste.

I wish I had such lovely data to work from.
I've had 5 months of cloudy weather in Melbourne.

cheers
Allan

[strongmanmike]

Nice Tri-ford Greg :thumbsup:

Lovely colours...the megenta may be just a taaaaaad iridescent pink and a taaaaaad saturated...I know, I know, coming from me...:rolleyes: :lol:

Mike

[Bassnut]

nooooo, flat dynamics (over compressed), no 3d, lacking detail, sorry Greg, stop rushing.

[gregbradley]

No that was all 16bit. I checked CCDStack. You can chose to save in 32 bit floating (I presume floating is the largest resolution as there are others like signed - not sure what that means). I am reprocessing the luminance and I think I need to repro it from the ground up with a different approach. As you say there is more depth in the image and the luminance is coming up nicely.



What you don't like it? Is it just too many stars? Yes it needs a redo and perhaps more data. No worries Fred.



Yeah I think this image is off the rails and I start over from scratch..

[alpal]

Greg,



Hi Greg,
Good luck with the re-processing - take your time.
You may also want to try one re-process just with RGB -
as the luminance can overpower bright areas & stars unless masked.
The results will be worth it with such good data.

cheers
Allan

[multiweb]

Colors and stars look real good Greg. I was just expecting a lot more definition in the core given your aperture. The two jets are a must. Maybe separate the 6 central stars too. No pressure. ;)

[gregbradley]

Thanks for the info Allan.



Yeah I liked the colour but the details were not so good. Perhaps it was seeing. I am doing another version where the details are coming up much more sharply but those core stars are burnt out still. Needed some short exposures. Luminance were 15 minutes.

Greg.

[AG Hybrid]

What an absurd and ridiculous picture. Look at what a Greg can achieve with amateur equipment. If they gave Greg the budget that NASA gave to those astronomers to image the most distant galaxy ever, he would probably be able to image the big bang itself and he would resolve it into sub-atomic particles!

[gregbradley]

Ok this image showed promise from the start but had some problems. I reprocessed this one a few times taking various approaches. A few versions didn't work out well enough.

This one did. Light deconvolution on the RGB and several strength deconvolutions on the luminance and those median combined. Looked pretty sharp and got rid of the out of focus look.

I found some Ha I took a few years ago to control the core stars so that was handy. Its good to keep the data intact.

I am happy with this one and I have absolutely wrung every last bit out of this one I can think of. Without overprocessing it either. It either comes out fairly quickly or its a fail.

The crop view is probably the best as the stars are all round. I think it was a slightly not properly seated adapter that caused minor tilt giving some elongated stars in the right side. Not too bad though and the widefield view is still pleasing.

CDK17, 3 hours (90 30 30 30 LRGB and 60 of Ha (bright stars in core only though). PME, STi guider, MMOAG.

Crop view:
http://upload.pbase.com/gregbradley/image/153044809/large regular size
http://upload.pbase.com/gregbradley/image/153044809/original large size

Widefield view:
http://www.pbase.com/gregbradley/image/152870200/large regular size
http://www.pbase.com/gregbradley/image/152870200 large size

Greg.

[multiweb]

Now you're talking. :thumbsup::thumbsup::thumbsup:

[Paul Haese]

Looks good to me Greg. :thumbsup:

[strongmanmike]

Hey, now we're talking...Sidonioing is a veeery worthwhile mental illness to catch :cheers: Quite an excellent Trifid now Greg, much better than teh first version, viva le repro :thumbsup:

Mike

[gregbradley]

Thanks Marc. I was determined to get a good result out of it!



Cheers Paul.



This site certainly keeps you honest. The standard is really high on this site. I'd go so far as to say its the premier astroimaging site on the net.
Other sites tend not to comment or don't give constructive advice. This site is very active and involved.

Greg.

[alpal]

Hi Greg,
That's a lot better - I knew the data was good.
The stars are smaller & far better controlled & I can see a hint
of the famous jet.
Just out of interest - did you stretch it in 32 bits with FITS Liberator?

cheers
Allan

[gregbradley]

Thanks Allan. The subexposures are handled in CCDStack and I did save the master subexposures as 32 bit. I create an LRGB colour combine in CCDStack not Photoshop. I suppose I can save the colour combine in 32 bit FITs and use FITs liberator. I had to resave as 16bit as PS wouldn't open the 32 bit floating. Come to think of it I got Eddie Trimarchi's plug in somewhere. I think that did the same as FIT Liberator.

Short answer - no. But I think I will try that out as above next time I do an image. The core stars were blown out in the subexposures so the Ha came to the rescue there.

Greg.

[Rod771]

Well Greg, I thought it was nice when first posted :o So I suppose its now Awesome!:)

And your right about IIS - best astronomy site in the solar system! :P I cant vouch for the whole galaxy :question: There might be some super dude's pointing their scopes in our direction.

[alpal]

OK Greg,
maybe give it a go next time in 32 bits.

The idea is that each separate stack of LRGB starts out in 16
bit from the camera but the stacking process will have 32 bit information.
Each of the 4 stacks - which are in 32 bits - can then be saved
as a 32 bit FITS file & then stretched in FITS Liberator -
using the same chosen stretching function.
Note: every image will require it's own unique function - so what
may be good for a nebula won't be good for a faint galaxy.
Each of the 4 files- LRGB stretched - can then be saved in 16 bit TIFF for Photoshop.
I do the combine in Photoshop using channels as I don't have CCD stack.
Photoshop will not allow a 32 bit stretch with "curves" so unfortunately
the 32 bit process cannot be continued there.
It probably doesn't matter too much as the data is compressed anyway
for it's dynamic range after FITs Liberator.

I am starting to always take some short 30 second LRGB exposures to counteract
those pesky bright stars which hit the well depth causing
their colour & brightness information to be lost.

Anyway - keep up the good work -
I am really missing being able to image owing to this Melbourne weather.

cheers
Allan

[RickS]

That's a very nice M20 now, Greg!

[Peter Ward]

Nice to see structure in the highlights. Yep. :thumbsup:

[TimberLand]

I agree with Rick. That does the setup justice, and looks like it should when it was taken with that top end bit if kit.

I had to adjust my monitor to see all the detail.

WOW. Love the dark dust and faint jet.


Justin

[gregbradley]

Yes perhaps we are in an image right now. We should remember to smile when we look up at the sky at night!



Thanks for that workflow Allan. I will check that out. I did similar in that I saved the stacks as 32 bit and then rgb combined them as 32 bit. But to open in PS it had to be 16 bit or at least not in that 32bit FITs floating format.



Thanks Rick. It'd be a good target for the Ceravolo. Perhaps next year now though.



Cheers Peter. It seems to be 2 groups of 3 bright stars.



Thanks Justin. I notice the CDK picks up Ha even without imaging Ha. That must be due to the large aperture.

Greg.

[sjastro]

Very nice image Greg.

Whether you find the site active and involved ultimately depends on who you are.
Over the years I've noticed the forum has become more clique orientated, if you are not in the clique you are given the cold shoulder.

Regards

Steven

[multiweb]

:violin:nah... it's all good fun. :P

[alpal]

I haven't found that.
This site & Cloudy Nights are the two best on the net.
I find some people are a bit secretive about their work flows
but that is up to them.
If I discover anything good I tell everyone.

cheers
Allan

[gregbradley]

Thanks Steven. Perhaps so. Its also a lot larger than what it was.





I sometimes check out Cloudy Nights but usually after someone has posted a link to a specific thread that relates to the topic.

Greg.

[tilbrook@rbe.ne]

That repro is stunning Greg!:thumbsup:

Love the rich colours from the nebulae to the stars.

Cheers,

Justin.

[gregbradley]

Thanks very much Justin!

Greg.