NGC7000 & IC5070 - A mixture of data..........

[swag72]

I am currently borrowing a friends OSC - A Starlight Express Trius M25C - It's an interesting beast for sure and has certainly got the thoughts about OSC's clear in my mind!

The chip on the OSC is MUCH larger than the 690 chip I normally use and so I used SGP to frame and platesolve and ensure that the data from the OSC was as good a fit to the mosaic with the 690 as possible. I did this as I wanted to experiment with using the colour from the OSC and the Ha from the mono camera.

A total break from my norm, so I welcome all comments, good and bad especially on the processing side. I really am a novice at this 'normal' imaging lark.

Details:

M: Avalon Linear Fast reverse
T: Takahashi FSQ85 0.73x
C: QSI690-wsg with 3nm Ha filter and Starlight Express Trius M25C

This is a 2x2 pane mosaic for the Ha data
29x1800s in Ha

And 35x600s with the OSC camera.

This has been combined using the Ha data in the red channel and then using it as a luminance layer as well.

Total exposure time 20 hours and 20 minutes

NGC7000 and IC5070 - The North American nebula and the Pelican nebula by Sara Wager, on Flickr

[astro mick]

Hi Sara.

Its a lovely image,very sharp,maybe a tad too sharp.With this one I don't get the impression of being immersed in the universe,as is the case with most of your images.It could almost be a painting,without the 3D effect.However this is a personal opinion,and in no way takes away the skill you have.

Mick.

[swag72]

Thanks Mick for your comments they are most welcomed. As I said, I find this sort of processing VERY difficult compared to the narrowband work that I prefer and love! If you say it's overly sharp, then it is and I need to re look at that.

There's a higher res version here  that may look a little better?

[astro mick]

Yes it does look better,but I will stand by my original comment Sara.

I would wait for more replys before you alter,as my comments could be rubbished,as other people I,m sure will see it differently.

As I  only use basic processing,i would,nt have a clue as to suggestions.

Always look forward to your images.

Mick.

[toxic]

great stuff Sara really nice 

[swag72]

.....Yes it does look better,but I will stand by my original comment Sara......

Your comment is totally valid Mick, if anyone feels it's too sharp...... then it's too sharp

great stuff Sara really nice 

Thanks Chris

[strutsinaction]

The hi-res is sublime. Congrats on yet another stunning capture. Keep 'em coming!

Regards

John

[swag72]

Thanks John

[swag72]

Anyone else have any comments? I ask as this one is dropping like a lead balloon and I'd love some more pointers on where's it's gone wrong

[HighlandBoy]

Stunning photo Sara. I only hope that I can some day take pictures to that quality, but a long steep learning curve ahead of me.

[theo]

Hi Sara,

I would agree it's a bit too crunchy but to me what is most apparent is that the image looks a bit washed out in certain area's particular in the dark dusty areas. It also seems quite noisy and i wonder if this comes from the OSC camera as the QSI's are normally very low on noise?? This is of course just my take on how i see it but as you were asking for pointers I thought I would give you honest feedback. It still a decent image though Sara and I'm sure you could reprocess it into a great one.

Pete

[swag72]

Thanks for the comments and Pete, that's just the sort of thing I am after - I am always willing to listen to peoples criticism, it's the only way to improve. This has been an interesting experiment with the OSC and I do have an RGB from the QSI that I processed after this one that I think is much better - So I clearly haven't worked out how to get the best from the OSC

[Barry-Wilson]

I have never tried to combine Ha and OSC data but my experience tells me that it is a tricky challenge and I think this is a spirited attempt: I do admire your creativity.  I would agree with Pete in that the 'blend' has resulted in an overly coarse image that does appear washed-out.  This a comment made relative to the usual high standard of your NB images.  The higher res version is an improvement over the first IMHO.

I have no idea whether you can improve on this image with its Ha/OSC blended data nor what techniques can be applied in PS to explore different outcomes: I have some ideas with PI, but no experience to draw upon to suggest if it would indeed be beneficial to use them.

Do please keep experimenting Sara, as I'm sure you'll crack the required techniques.

Barry

[swag72]

Thanks Barry that is very insightful - Thank you for taking the time to answer. 

I think I'm giving this one up as a failed attempt. I hope that I won't have the OSC for too much longer, so it's not something that I wish to perfect and a skill I want to hone really. I have found that adding Ha to the red channel of a mono image seems to give far less problems....... it seems to be the OSC that is causing issues for sure.

I'm glad that I have been able to dabble in the OSC world. It has certainly scratched an itch that I always had, wondering if a OSC and mono was a good combination, or even if a OSC was any good for me at all

[ollypenrice]

There's a lot to like in that one. The local contrasts in the bright nebula are very pronounced. It's often rather dull and flat but not here. You've also brought out considerable degrees of distinction between very sooty, obscuring dust and more tenuous, paler, dust around it. Often we just get a black silhouette but here there are gradations. The price is that etchy texture that gets called 'crunchy' and I think that problem is there. I wonder if, having got the stretch hard enough to get the dust distinctions showing, it might be worth pinning them at that point and then only stretching above them? The difference in S/N in the dust and S/N in the nebula is so enormous that one stretch won't fit all.

Good job on keeping the stars down.

On the sharpening again, maybe upping the pixel scale limit would help. (If using USM in Photoshop that would mean increasing the 'Threshold' value.)  So you'd sharpen only on larger rather than on smaller scales. CCD noise is small scale and gets boosted by small scale sharpening.

To keep the noise down in the dust you really need what you won't easily get from the OSC and that's deep luminance. That's the dust buster!

Good image, though.

Olly

[swag72]

Thanks Olly for those observations - Very much appreciated. 

I have another OSC / mono Ha image sitting in the wings - Tried to take on board these comments on this next image.................

[ollypenrice]

OSC and mono Ha/O111 is a perfectly valid way to work. I did quite a bit of it at one time. However, luminance is so fast - I think four times faster than RGB/OSC from casual measurement.

Looking forward to the next ones!

Olly

[Coco]

Looks marvellous on my IPS 1920x1200 Dell monitor, I can’t make my mind up on the blue points (stars) I think I like them a lot if I'm honest, also the California area looks positively 3D! Almost lifting itself of the screen.

Definately top drawer Sara. 
 

[pietervdv]

I have my doubts if a pure HA layer is a good base for an RGB image. I think it should be built up from a deep Luminance shot and the HA should

only be very selectively mixed in the red & L channel. Mixing narrowband and broadband data is very tricky...  But, it is a nice image in any case!

Pieter

[ollypenrice]

I have my doubts if a pure HA layer is a good base for an RGB image. I think it should be built up from a deep Luminance shot and the HA should

only be very selectively mixed in the red & L channel. Mixing narrowband and broadband data is very tricky...  But, it is a nice image in any case!

Pieter

I only apply Ha as luminance at very low opacity, if at all. I wonder, Sara, how much Ha you applied as L?

Olly

[swag72]

Thanks Guy and Pieter - I've not been entirely comfortable with this OSC working to be honest

I only apply Ha as luminance at very low opacity, if at all. I wonder, Sara, how much Ha you applied as L?

Olly

I've just had a look at this in PS and it appears that I added about 45% opacity as luminance..... Too much? It seemed really washed out without it.

[iksose7]

Anyone else have any comments? I ask as this one is dropping like a lead balloon and I'd love some more pointers on where's it's gone wrong

Its a nice image Sara and judging by your Flickr and Facebook its not doing all that bad!

I dont think its too sharp at all, when viewing full size that becomes apparent but there was something about it not clicking with me personally, hope you dont mind but i had a little play to better understand what exactly. I found dropping the midtones a little while protecting the nebula and stars, and then applying a global saturation decrease gave what i would describe as more of a 'typical' NA nebula image, though it is up to you if you want it to be typical or not

Callum

[swag72]

I'd be more than happy for you to post your edit if you still have it Callum - It's all about learning after all and this will be a good demonstration.

Sadly I fear that this ....

.... I found dropping the midtones a little while protecting the nebula and stars,.....

..... probably involves Pixinsight, which rules out the same process!

[iksose7]

Here you go, and yes it involves PI! I wouldnt have a clue how to do it in PS

I think this looks a bit more traditional for this neb but thats just me! Traditional is not always best

Callum

[swag72]

Thanks Callum...a nice rework that pretty much matches what I did in PS after your comments. Many thanks indeed