California nebula in HaRGB

[swag72]

I wasn't going to post this on here as there's some truely awesome examples already posted - But hoped that perhaps people may look at it and be able to say how it could be improved.

This is somthing of a collaboration - although not planned as such. I collected the Ha, R and B and decided to synthesize a green channel as the weather turned. However, it really didn't work and so Olly kindly sent me some green data so that I could try to do a proper RGB. Thank you Olly!!!!

I learnt that indeed a real green channel makes a massive difference, so there'll be no more sythesizing of the green channel from me! This was processed at least 6 times according to the folder on my PC and I got to a stage where I don't think I can do it any better. I need massively more processing time on RGB images. Olly .... poor Olly!! ..... was on hand with help as always and without his time and effort I wouldn't have got it to this stage. My first couple of processes were very red in comparison and I was surprised when it was pointed out to me that it really is more on the magenta side. Star colour was a battle as usual and it's not quite as I would like, although definitely an improvement on previous tries.

Enough drivel!! Anyone have any thoughts or comments then I will gladly take them on board, we'll never learn otherwise.

M HEQ5

T Pentax 75SDHF with Optec NexGen reducer

C Atik 460EX mono with Baader R,B and 7nm Ha filters and green from Olly

20x1200s Ha

28x300s Red

24x 300s Blue and about 1 hours of green data.

[Gina]

Great image - well done

[ollypenrice]

Fantastic green detail!

Heh heh, only joking. I liked all your versions of this one and probably thought they were better than you did, but this is a good'un, most assuredly.

Olly

[swag72]

Thanks Gina, and Olly, I sure would have struggled without your help. I think I've also learnt to keep an eye on the whole image as you do each bit. I was concentrating on a potentially problematic star and as a result lost sight of some smaller stars that were getting a little out of hand!

[robin-m]

You shouldn't be afraid to post just because others have posted similar and in your eyes possibly better shots. I've posted some real shockers (which yours isn't btw) and the comments have always been helpful and constructive. You have to remember that some images have been produced with really high end gear whilst others are done on a shoestring. Each has their own merits and is worthy of praise.

Yours is a good image that I would be happy to post, well done.

Robin

[swag72]

Thanks Robin. I am my own harsh critic and I've never yet taken / processed an image that I am truly happy with. it's more to do with how I feel about the images themselves than how they compare to others. I have an unrealistic wish of perfection!

[ollypenrice]

Thanks Robin. I am my own harsh critic and I've never yet taken / processed an image that I am truly happy with.

No good imager ever has.

Olly

[robin-m]

No good imager ever has.

Olly

And the not so good ones like me as well!

[TakMan]

Very nice Sara, particularly the dusty transition from the bright nebula to the darker areas...

Plenty of 'energy' coming from the billowing dust running through it...

And you've got it sitting nicely in the frame also!

Damian

[swag72]

Thanks Damian, I appreciate you taking the time to comment. I have learnt in this processing lesson that you really can not take your eye off any thing in the image. I was concentrating on a brightish star and not wanting to push it too hard, meanwhile didn't look at how the litle ones were doing!! Note to self - Watch the whole image!!!

[Coco]

Now I like that alot, its practically illuminous ...

Shame its not all in there with some surounding clear star fields.. I like it alot..

[andyo]

I wasn't going to post this on here as there's some truely awesome examples already posted

Looks like this is another awesome example very nice and really well framed

[swag72]

Thanks very much Guy and Andy. I would have liked a little more breathing space around the nebula, but sometimes we just have to accept our field of views!!

[Mark72]

Nice work Sara.

I like the details. Overall it gives 3D look. I'm not sure why the colour should not be red.

Mark

[James]

You shouldn't be afraid to post just because others have posted similar and in your eyes possibly better shots. I've posted some real shockers (which yours isn't btw) and the comments have always been helpful and constructive.

I think Robin hits the nail on the head there. It's a lovely image with some great detail in their including the dark areas.

I too have posted some shockers but they are now either buried in the archives somewhere or have been surreptitiously replaced with better versions that I've done later

James

[swag72]

I am not absolutely happy with posting anything that I can look at and see problems - I want my images to be perfect - Don't want much do I?!!

Regarding helpful and constructive criticism, I do find that happening less and less on SGL, which is a great shame. I think that if you are just learning then the comments are very helpful about have you tried this and that etc, but once you get to a more middling standard there is much less 'help', if that makes sense. I have probably sealed my coffin now on any further comments on SGL ( ) but I would love people to be super critical about the images posted so that people can continue to improve. While a raft of 'nice shot' etc is heart warming and nice to receive, it's not very helpful as such. I'm as guilty as anyone, and it's difficult to be honest about peoples images when there's a load of 'good shot' comments when there are clearly some issues that need to be addressed and you are going to be the first person to say them. It's also a very fine line to pick to encourage people as we all had to start somewhere ..... Anyway, enough from me, just felt that I needed to get that off my chest!!! I reckon I'll not be posting any images for a while!!!

[Mark72]

Point taken Sara,

I'll be ruthless next time:)

But may be you are mistaken. If the image clearly needs some more work but already shows something descent the imager may be well aware of this.

It's always nice to hear a warm word or two and a lot of critique can be rather disappointing. What the image needs most is more data and it's not always possible.

Mark

[swag72]

Cheers Mark - My comment was in no way a dig at you or anybody in particularl, just a general obervation and feeling that I have! I do agree that too much crit can be disappointing, but it does depend how you personally take it. I'd be more than happy to have my images ripped to shreds and then I can pick myself up, dust myself off and vow to do better next time. It's hard to know how individuals will take criticism.

[opticalpath]

It's a fine image, Sara, and any constructive criticisms would really be nit-picking ......... but since you asked .......

- The red channel highlights are slightly clipped, affecting a few small areas of the nebula and the colour of some of the mid brightness stars.

- The sky background where (I think) it should be neutral has a slight red cast (bottom left corner area for example) I thought it looked better with a small colour balance adjustment (red towards cyan) in shadows.

- A lot of the mid-brightness stars are a bit too orange imo; there should be more yellower tints amongst them (i.e. more green?). Red channel is saturated in some of these stars, which may be contributing.

- I think the image is mirror-flipped left to right (if anyone's bothered about that).

As I said, this is really nit-picking, and maybe largely a matter of opinion and personal preference. I would be very happy to have produced that image.

I do agree with you about feedback: I would welcome more specific criticisms (positive and negative) to help me really get the best out of the hard-won data. Other members' opinions and specific suggestions are always valuable.

Adrian

[swag72]

Thanks Adrian!! Nit Picking was just what I wanted to hear!!

I did lose sight of the smaller stars as I went along, and did get a *little* carried away with Noels star colour action! I'm not hugely surprised that you suggest there should be more green. Olly gave me about an hours worth, while my red and blue was about 2 hours worth. Serves me right for being impatient!!

I don't know how the red channel became clipped - I'll have to keep an eye on that as I go along as well and the reddish background changed - Perfect!!

Who knows what way up these damn things should be?!!!! It took me ages to try to get it this way round!!!!

So now I have some more pointers about things to watch out for in my next RGB process - Thank you!!

[opticalpath]

... did get a *little* carried away with Noels star colour action! ...

Noel's action is great, but it does magnify any small colour imbalances or artifacts. I've found it can quickly saturate a colour channel if you apply it several times. Also any small mismatches in the sizes of stars in R,G, B can turn into colour halos after a few iterations, and tiny colour misalignments become brightly coloured blobs at the edges of stars! I found it helps to separate out the luminance and to blur the colour layer slightly after each application of the action to it. That softens any extreme colour effects.

Adrian

[ollypenrice]

Good thread. Good image. Good fedback.

Olly

[swag72]

Adrian, that sounds interesting and something to give a go as well. Do you use Gausian blur and if so, how much would you blur it each time?

[opticalpath]

Adrian, that sounds interesting and something to give a go as well. Do you use Gausian blur and if so, how much would you blur it each time?

I use Gaussian blur, Sara, but tbh I haven't experimented with other methods since it works OK. It needs to be quite a small radius - maybe about 1 px. But it varies depending on how many iterations of the action I want to use and on how bad any colour artifacts/ imbalances are. The blurring needs to be enough to smooth out the colour and suppress colour hot-spots from appearing, but not so strong that it desaturates the star colour and defeats the object of applying the action. I usually blur the colour layer a little before applying the first star colour action and then again before subsequent applications as necessary, depending on how/ if artifacts appear. In practice, I rarely apply the action more than twice, though; if it needs more than that, the star layer probably needs some more work to strengthen it first. Sometimes I duplicate the colour layer and have two versions, say, with one and two applications of the action respectively, then use masking to apply the blurring and the action amount selectively, if there are a few particularly troublesome stars for example.

Adrian

[Fay]

Really lovely california Sara!!

Fay