Soul Nebula (IC1848) - DSLR

[Christopher Davenport]

Hi

I have noticed that there are not many Soul nebula DSLR images about. Other than some really wide field images of both the heart and soul together.

I decided to give this a go as I have had my DSLR modified with a baader filter, increased sensitivity to HA.

I just received my light pollution filter (astronomik CLS) and boy what a difference it makes

Last night was my first outing with it in place, so I used the opportunity to push both exposure times and ISO as high as possible.

I settled on 600s at ISO1600, which is just amazing, considering my previous washout point was 180s at ISO1600 or 300s at ISO800.

These used to happen on my 80ED with a reducer on it to get it down to F4.5, making it abit frustrating on HA targets.

So I do have some questions for the veterans out their, post stacking 36 subs, 36 darks, 36 bias and 18 flats: (Cappa Sigma)

Firstly my image has a hazy quality to it, which is either due to focus or guiding errors or stacking?

Secondly on closer inspection many of my stars have dark cores, (creating halos) as the histogram had a lot chopped off the top. 

Lastly my flats worked really well for a change , but the image was still sightly lopsided as the center point of the reducer was not lined up to the center of the chip. this causes stars  in that corner to be stretched and so some cropping was necessary. 

Anyway, much processing later, mostly the removal of the dud stars, I have the final product to show for it.

This nebula is fantastic, it looks so much like a newborn in the whom, I think I have actually accentuated it in my processing.

I also love all the star forming regions at the bottom, looking like the pillars of creation. 

If you have a DSLR version of this target please post it as I would love to compare.

If you have suggestion, comments, criticisms, etc please post them.

[wxsatuser]

Looks like you have some nice detail in there but it looks a bit dull for 600sec subs.

May be this is just the processing and something better is waiting to come out of the data.

I assume this was with the 80ED setup at f4.5?

The CLS is a big plus and worth every penny.

[Christopher Davenport]

Looks like you have some nice detail in there but it looks a bit dull for 600sec subs.

May be this is just the processing and something better is waiting to come out of the data.

I assume this was with the 80ED setup at f4.5?

The CLS is a big plus and worth every penny.

Mike,

Thanks for the feedback, and yes, this is the 80ED at F4.5.

I find that the data is quite blocky down in the detail on a zoom, assume this is causing it to be dull. (cartoonish)

All processed in DSS and PS5, maybe it is because my initial stretches are to hard or it could be the cappa sigma stacking.

I have removed all the small stars to medium stars as they all look weird.

I will see if I can sort some of this out on another processing round over the weekend.

Although I think it is something to do with the capture, I have a sneaky suspicion I should have stuck to ISO800.

[Rico]

Theres nothing wrong as such with using ISO1600, I use it all the time and never really have much to complain about. It might turn out noisy, but lack of sharpness/detail never seems to be a problem. Could it have been slightly out of focus to start of with? What does the histogram look like in the original image - is the all the nebulosity data at the lower end of the distribution? I would also check what your calibration frames are doing. These can sometimes make things worse. Did you do any Noise reduction?

[Christopher Davenport]

Theres nothing wrong as such with using ISO1600, I use it all the time and never really have much to complain about. It might turn out noisy, but lack of sharpness/detail never seems to be a problem. Could it have been slightly out of focus to start of with? What does the histogram look like in the original image - is the all the nebulosity data at the lower end of the distribution? I would also check what your calibration frames are doing. These can sometimes make things worse. Did you do any Noise reduction?

Yes a tried a bit of noise reduction and sharpening in PS. Post stacking my stars looked really odd. Dark with bright halos. I think it must be my flats.

How do I check focus on the histogram?

[wxsatuser]

Try a stack without the calibration frames.

I find sigma clip is a must here to get rid of aircraft/sat trials and don't find it a problem.

DSS reports the FWHM for each frame, it's on the far right of each frame detail, don't know how accurate it is.

[Rico]

You can't check focus on the histogram, I was just wondering what the histogram looks like for the original image. 

I think the NR has made it a bit blotchy and you've lost sharpness and detail through that. Its cracking shot anyhow! Any chance you can share the stacked tif?

[Christopher Davenport]

Sure will upload onto dropbox

[Christopher Davenport]

My DSS fits, so no processing other than a stacking.

https://www.dropbox.com/s/oti2izxlhjt94ab/Autosave.fts?dl=1

You can open this in DSS, Astro Tools, etc and save as a tiff if you want to edit it in PS.

[Rico]

I'll have a look at it now. 

[Rico]

I think some level of processing was done on the stars by DSS, which seems to have tried to regain some detail in them, but not very well. I've never used kappa sigma clipping, so maybe disable this? did you have anything set under cosmetic settings? 

[Christopher Davenport]

I think some level of processing was done on the stars by DSS, which seems to have tried to regain some detail in them, but not very well. I've never used kappa sigma clipping, so maybe disable this? did you have anything set under cosmetic settings?

I think its the calibration files probably the flats some times my flats cause more problems than they worth.

I will restack without the flats and see what it looks like.

[Rico]

Once you get rid of those artefacts around the stars, you'll end with a great image! I had a look and my normal processing techniques were difficult to apply because it just brought this artefacts out more and more. I'm not saying this process is any better (it was a very quick one) ... but you can see what I mean. Its difficult to sharpen this without dealing with those stars. 

Good luck! Let us know how you get on.

[Christopher Davenport]

Hey Rico,

I really like what you have done there.

I guess I was chasing down the stars in post processing and I messed up the nebula in the process.

I am going to try various different stacking techniques and see if I can get to the bottom of the problems with the stars.

Then I will reprocess on my usual routine.

[Christopher Davenport]

Hi Guys,

So thanks for all the tips, I have taken on board everything described on here, plus I have given the image a good walloping of more data.

So it has about 2hrs of 180s subs and about 10hrs of 600s subs. The 180's have helped me with the stars and the dubbling of the 600s, has given the nebulosity far better detail.

I have performed selective sharpening on key areas, like the face and lastly a slight noise reduction at the end.

Hope we enjoy the improvement.

If there is still something striking or if you have any tips let me know. 

Thanks again.