Try my data: LRGB Ha, M8 Lagoon Nebula.

[alpal]

Would anyone like to try some LRGB processing?
Please post your results in this thread.

I finally did some darks, flats & bias frames for my first
LRGB picture & the results were so much better.
Details:
8" f6 Newt with QHY9 camera.
3 x 3 minutes of each of LRGB
plus 10 minutes of Ha 7nm.
Total 46 minutes of data.

A small version is attached to this post.

Here is a large version 1.2 MBytes:

http://www.flickr.com/photos/24719437@N03/7988256388/sizes/h/in/photostream/

It's my 4th attempt - you can see the others on my flickr photos
before I added the Darks, Flats & Bias frames all at -35°C.
I still wish I could get a little more colour in those bright stars.

For anyone who wants to have a try the data is here:
(each file is 17.6 MBytes & look for the bottom of the page to download them )

Stack of Red:
http://www.sendspace.com/file/qwuojx

Stack of Green:
http://www.sendspace.com/file/dg0axg

Stack of Blue:
http://www.sendspace.com/file/noxcdm

Stack of Luminance:
http://www.sendspace.com/file/sajxau

Stack of Hydrogen Alpha, Baader 7nm:
http://www.sendspace.com/file/anhsnu

[Peter.M]

I would love to have a go at your data, however I would advise that other people do not. The site you have uploaded the files too installs various spyware on your computer, I am confident I can remove it but others may not be.

If you open a web browser Alpal does the default page say anything like "incredibar" ? If it does I wouldn't be using that computer for any internet banking.

[alpal]

Hi Peter,
I've been using sendspace for years without any problem.
I have Norton 360 - fully paid version & it hasn't picked up any problem.
I don't get incredibar or whatever that is.
By spyware - do you mean cookies?
Every site has cookies these days.

cheers
Allan

[Peter.M]

Here is my go at the LRGB data, I didn't incorporate the HA into it (it was still downloading)

After downloading the first image my computer has been infected with spyware, Spyware is like a virus but slightly different I don't know if nortons will pick it up (it should). I might have just got unlucky but i doubt it.

[irwjager]

Hi Alpal,

The Luminance exposure is really quite short and noisy to be of any use. Typically you would spend extra time gathering Luminance and spend comparatively less time on the RGB, as the latter is more forgiving when applying noise reduction as the eye is less sensitive to color, but more to brightness. Currently your RGB (3x3x3 minutes) data is actually a better luminance source than your Luminance data (1x3x3 minutes).
If found the Ha is too noisy to be of any use as a partial luminance data, so, in the end, I settled for just processing your RGB data and came up with the following (attached).
I did notice though some sort of anomaly (dust donut?) at 7 o'clock.

Cheers,

[alpal]

Hi Peter,
You've done a good job on that picture.
You've got some nice yellow colour in some of those stars.

I just did a complete scan with Norton 360 & it found & deleted 37 tracking cookies - that's all.


Here is the Norton website report for sendspace:

http://safeweb.norton.com/report/show?url=http:%2F%2Fwww.sendspace.c om%2F&product=NIS&version=19.8.0.14&layout=Retail&lang=0901&source=toolbar

I think you have a problem caused by some other factor
although how can we be sure of any website these days?
All we can do is buy the best security package we can & go from there.

[alpal]

Hi Ivo,
That is a very nice job you've done there.
That's much better than what I did.
You are right about the noise & the dust dougnut.
The flats didn't get rid of it completely.
I will track down where it is and remove it from my optical train.
It is probably on the camera nose piece window.

The luminance was also 3 x 3 minutes i.e. 3 subframes frames each of 3 minutes.
So was the red, green & blue.
The Ha was only one subframe of 10 minutes.

cheers
Allan

[multiweb]

Very sweet repro - gorgeous colours and contrast. :thumbsup:

[irwjager]

Thanks Marc. I actually realised I had a bug in the interaction between Wipe and my noise reduction routine, leading to a noise reduction that was too aggressive at places. The core should exhibit much more detail now. Stars could use some work, but it's a quickie :P


Yes, so for your luminance data you are working with 1channelx3minutesx3exposures, while for your RGB data you are working with 3channelsx3minutesx3exposures. This is why the luminance data that can be derived from your RGB data is approx. 3x better (not taking into account filter response - the real figure is probably a bit worse). :)

We could probably create better aggregate luminance data by making a weighted average of 0.75x the luminance data from your RGB set and 0.25x the luminance data from the luminance-only frame... :question:

[alpal]

Ivo,



Yes Ivo,
I see what you mean now.
There wasn't enough data for a top pic & it was from
an outer suburb of Melbourne with light pollution.

The transmission curves for the filters is here:
http://i262.photobucket.com/albums/ii119/alpal2002/NewRGBfilters.jpg

You can see a large hole between red & green which helps
to knock out the 2 sodium lines from street lamps.
The luminance filter is picking up all the light pollution which doesn't help.

Your sceond attempt looks a lot better in the center of the nebula
but really needed a vector mask so that it didn't sharpen the less brighter areas.

cheers
Allan

[irwjager]

That's a nice filter set indeed, with good transparency;
97% R
90% G
91% B

Given the light pollution, it may make more sense to shoot just RGB and Ha instead?


It's virtually the same image, with the same amount of decon applied, but with less noise reduction in places. Because there was more detail left over this time around, I suspect it's the very heavy JPEG compression (45% to get it under 200kb) that is killing me here. :(

[alpal]

Hi Ivo,
You're right,
I used 90% of the RGB data & combined it with 10% of my old picture
& I came up with this result.
I don't think it's worthwhile taking luminance from anywhere with light pollution.
I think this pic looks a lot more tasteful than my original pic which was too orange?

[irwjager]

Wow, that's a great improvement Allan - looks like we have an winner! :thumbsup:

[alpal]

Thanks Ivo,
I did a lot more processing on it using Photoshop & Fitswork 4.
I removed the huge dust doughnut, improved the star colours,
improved the gradients, boosted areas with masks,
did a little bit of sharpening & contrast using vector masks.
I cut & paste the stars from one of the first versions back in
to work on them for colour as they were washed out.
I deleted all the previous versions on flickr.
I ended up with 18 iterations to get this:

http://www.flickr.com/photos/24719437@N03/7996118724/sizes/h/in/photostream/

I think that is a lot better?

cheers
Allan

[atalas]

Hi Al

Looks great!well done.

[alpal]

Thanks Louie,
I am thrilled to get such a nice pic for my first use of the QHY9.
I think it's maybe the best pic I've ever posted & I can't wait to get the system perfect i.e.
find the source of that big dust dougnut &
get the RCC at the best spacing -
I don't think it's more than +/- 1 mm out.
You can see elongation of stars in the corners.

It was also great that other's had a go too.
We can always learn from each other.

cheers
Allan

[Ross G]

Hi Allan,

Amazing photo for your first attempt.

Looks great.

Good luck with the fine tuning. Your setup has great potential.

Ross.

[alpal]

Thanks Ross,
I will borrow some T42 adaptors tomorrow night -

spacer rings ....I’ll experiment with 2 x 2 mm,1 x 1 mm and 1 x .5 mm – adding or subtracting -
to fine tune the RCC coma corrector spacing as there is still some small coma in the corners.

I am very happy with my first attempt.
The quality of the data leaves my old DSLR for dead.

cheers
Allan

[alpal]

A further re-process/ refinement:

Larger file here:http://www.flickr.com/photos/24719437@N03/8014448937/sizes/h/in/photostream/