Helix Nebula with 111 hours of data

[Paul Haese]

Well, I think I can finally say I have reached the realms of diminishing returns on this target. I have now collected 111 hours of usable data. I have rejected about 28 hours of data in total, making total collected of 138 hours. Slight guiding errors, cloud and the moon being too close have been the main reason for rejection.

In the end I stacked the following:

60 hours in Ha
39 hours in OIII
12 hours in RGB (4 hours in each)

Some things I noticed as time went by.

1. The extra hours in RGB really worked well to show the star colour and smooth the image. I used lighten mode for the addition of the RGB and in several stages. Of interest is the galaxies that have shown up in the background. Whilst there are not hundreds there are a few more than you might expect. I have spent quite some time looking and deciding what is a faint star and what is a distant galaxy. A perfect example of integration have an effect.

2. Dithering becomes really important at this duration and I am going to reconsider my current dithering settings for future images. I noticed some fixed pattern noise appear over time despite dithering of at least 6 pixels. The Ha data I stacked 120 frames and so the dither was deficient for that many frames. Some subs were obviously overlapping.

3. Signal strength climbed slowly the point where some elements of the Helix look as solid as the central core. The outer reaches in particular took a lot of time to get to a point of solid definition and I suspect it would be a quite a lot of hours more to gain further definition and that gain would not be worth the extra hours. I added 29 odd hours to the previous version of this image and it took all that time to make the outer reaches appear more solid and brighter.


Click here (http://paulhaese.net/HelixNebulaDeepFSQ.html) for larger resolution image.

I think this image looks better than the previous version. I have cropped this image to remove a very bright flare from a star on the edge of the field, but essentially the full res image is at 100%.

[andyc]

Ah dammit, that's good! :bowdown: Slightly mesmerising - if I look into that eye long enough I'll be hypnotised by the great astro-deity Paul!

[rustigsmed]

amazing stuff Paul.

I really find it interesting how images progress along the way with more and more data added.

cheers

[RickS]

Great job, Paul! As deep as I've seen...

[Placidus]

That's pretty definitive.

Just had a fun half hour comparing the two versions. The main change seems to be a slight change in the colour, with the iris bluer and the eyebrow noticeably more magenta/red, less orange. The stars are a tad sharper, but I wonder if some of the faintest filigree in the nebulosity isn't sharper in the previous version.

Noise level is utterly negligible.

You've done a great job in maintaining the details in the cometary knots in the iris, showing the faintest outer features, and somehow, magically, maintaining the feel of their mutual relationship. Magnificent processing.

There's an orange-red blob at about ten o'clock which I'd often thought might be a face-on barred spiral - it has that look in just about everyone's shot - but you've convinced me it's actually nebulosity. I wonder if it's a part of the Helix or if it's just line of sight.

[topheart]

Congratulations!
Interesting observation about the dithering when there is a massive number of subs....

Thanks indeed!
Cheers,
Tim

[Stevec35]

Another great megadata exercise Paul and as deep as I've ever seen the helix! It's amazing how 3D it now looks. One thing I noticed though is that the bright stars have dark centres in them. It's only a small point but I sometimes get told off when I do that.

Cheers

Steve

[AG Hybrid]

Fantastic as usual. I suppose now you've reached the point where diminishing returns on exposure time are not providing enough usable data?

[Paul Haese]

Thanks Russell and Tim for your comments.



LOL, I seriously doubt that. Thanks for the compliment though.



Thanks Rick. Several dudes on CN seem to think otherwise. Funny reading some of the comments there. I think it is about as deep as an FSQ can go.



Thanks MnT. Maybe I sharpened some areas slightly differently this time and hence the different looking nebulosity. The cometary globules need to be reduced in brightness a lot as the data builds. The integration inevitably brightens that region right up to the point of being burnt out. I don't know what that blob is, but I think it is part of the nebula. I suppose it is possible to be completely separate and distinct from the nebulosity. :shrug:



Thanks Steve, I think that might be a jpeg artefact with the stars. I just checked to see if there is any dots in the Tiff and there are none but I think I can see them on the web image. I did not apply any compression other than the format. Hmm not sure the cause.

I agree about the 3D look. Some of the processing tricks I use tend towards that look and more so with this vast volume of data. I have always wanted to create this sort of image for this object. It's such an interesting planetary.




Thanks Adrian. The main thing I noticed in the last 10 hours of data was that there did not appear to be vast improvements on the signal. The noise in the Ha and OIII was fairly static too. I could easily go on and continue to collect data for another 20-30 hours before the season is over but I figure it would only be an experiment rather than for improving the image.

[Atmos]

Can so just get lost in that Helix, brilliant image and very well processed :-)

[gregbradley]

Congrats on your highest ever exposure. It'll stand as a record for some time (unless Rolf decides to do one!).

Nicely processed and a great look to it.

Greg.

[DJScotty]

Paul that is a superb image. So much detail.
So much patience! 😆

[Rod771]

Fantastic, Paul! Very deep indeed. :thumbsup:

[SkyWatch]

Top effort Paul: looks fantastic! It is incredible what a 4" scope can do.

Regarding the dark patches in the bright stars: I am wondering whether this is just a contrast effect: if you maximise them on screen and put a white mask around the star the "dark patch" is reduced considerably...

Keep up the good work!

Dean

[Peter.M]

My favorite part is the bunny ear extensions to the bottom left!

[E_ri_k]

Wow! I love it, great detail around the blue area. I like points 1 & 2 you made, something to consider in the future. Star colours look great, and oh yeah...where do you find the time & clear skies, you seem to be pumping out a few images!

Erik

[Peter.M]

I have heard around this forum that sometimes the software dithers in a non random way, so regardless of what setting you use it will eventually image the same spot more than once. You may only be noticing it with really long exposures because it has time to accumulate in the average. You could try stacking with a different algorithm?

[LewisM]

Wow, 111 hours, and it's Sidonio Pink too :P

Impressive.

[Paul Haese]

Thanks Colin, Scott and Rod for your comments.


Thanks Greg, its been epic, but no doubt Rolf is already planning an image of this target. Perhaps this might stand as a record for a 4" scope on this target. In any case, it was an exercise just to see what was really capable of being capture. Alas not much more if any more than other images of lesser data capture I think. :shrug:



Thanks Dean, hmmm you could be right about the contrast effect.



Thanks Erik, clear skies is a rarity but automation certainly makes the collection of data easy. I basically set an imaging run around late afternoon and then once it starts I take a look at the start and then the system takes care of the rest.



Thanks Pete, I tried three stacking algorithms. I tried mean, median and sum and each has the same results once I stretched the data. Although not entirely the same result, it was quite similar. Maybe I should try stacking stacks of say 20 and then stacking the resultant stacks. Perhaps the result will be different. :)



Thanks Lewis for the compliment. :)

Didn't know that the colour had been reserved. ;) Though my aversion to magenta is not to do with the nebulosity but with the entire field having that particular cast or any other cast for that matter. Despite the fact that hydrogen is the most abundant element in the universe I doubt it exists in such volumes and is excited to the extent that it would create a magenta cast in all parts of the sky. Maybe I am wrong. :)

[Spookyer]

Think that qualifies as MEGADATA!

[Slawomir]

Fantastic image Paul, history in the making :thumbsup:

[SimmoW]

Wow, so you're starting world records now Paul! Stunning image, yes so 3D

[RobF]

Nicely done Paul.
I morn for the 28hrs that didn't make the cut, but what's left is a fascinating image. Go the FSQ!

[John K]

Wow Paul,

You really have outdone yourself with this image - great interpretation - brings out the structure of this amazing object and the coloured star field adds another dimension.

Clear skies,

John K.

[Paul Haese]

Thanks Brett, hmm just I reckon. ;)



Thanks Slawomir. :)



Thanks Simon, not a hard world record to break though. Just be persistent and collect 112 hours. ;)



Thanks Rob, don't morn for those hours, they were not worthy. :)



Thanks John, I really think the addition of the star field sets this image a little apart from other images of the Helix. Doing a deep star field really puts the object in context of what is behind and where it lies.

[marc4darkskies]

Only 111? C'mon Paul you woose - keep going!! :P ;)

Wonderful image Paul. :thumbsup: The faint extents are very well defined now and colour looks spot on (on my crappy work monitor at least!)

Cheers, Marcus

PS: I have my camera back - waiting for the weather to star test

[Paul Haese]

:lol: I thought stopping at a palindrome seemed fitting. ;)

Nice to hear you have your camera back. Mine is still going well (fingers crossed) Looking forward to seeing another image from you.

[Regulus]

Magic. A nice image to just stare at.

LOL

Trev

[Shiraz]

that was well worth the effort Paul - everything about it just looks "right".:thumbsup: Congratulations.

[Bassnut]

wow, thats a lot of hrs Paul, the neb extention is nuts with next to no noise.

[Paul Haese]

Thanks Ray. Is anything ever really right in this game? :) I am glad I undertook the project. Its been interesting to watch the image develop over time during the last 4 months.



Thanks Fred. I now have some appreciation of what you must go through when imaging your mega data images. When is your next image due out?