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Narrowband Elephant's trunk


Martin-Devon
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With very little data relatively, you've got some nice colours. But for me the noise reduction is just too heavy handed. On the right hand side of the image it looks very smeared and almost like you've used a dob of vaseline, under the trunk especially. There's a marked difference with the left hand side of the image.

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Thanks for your comments Mark and Ian.

Sara, I've looked at several recent posts of the trunk, including your own H-alpha only version on 3rd June, and to be frank I don't see a lot of difference from mine. I've cropped and then expanded my image which will lose a degree of resolution, and also added OIII/SII to make a full narrowband - these are rarely as sharp as pure H-alpha only images but they do add lovely colours.

Martin

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Hi Martin,

I am sorry that you felt that my comments regarding your post were OTT. I didn't mean to offend in any way, either you or others that read my comment.

I guess that images are always down to personal taste. I hope that you will accept this apology in the true manner that it is meant.

Regards

Sara

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Well, you've got the colour for sure - maybe needs a bit more OIII as its very weak in this area. Still good anyways!

To sharpen this baby up - shoot a load more Ha (like 4 hours worth) and use it as a luminance layer (processed with contrast enhancement and high pass filters). Reduce the star size in the colour layer (to prevent halos), then blend it in - jobs a good un :)

This method doesnt work all the time, but I can confirm that is does on IC1396 as the OIII and SII does not really contain any extra structure... well, maybe a bit in SII but its not like youre missing the nose off the mona lisa :)

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Well, you've got the colour for sure - maybe needs a bit more OIII as its very weak in this area. Still good anyways!

To sharpen this baby up - shoot a load more Ha (like 4 hours worth) and use it as a luminance layer (processed with contrast enhancement and high pass filters). Reduce the star size in the colour layer (to prevent halos), then blend it in - jobs a good un :)

This method doesnt work all the time, but I can confirm that is does on IC1396 as the OIII and SII does not really contain any extra structure... well, maybe a bit in SII but its not like youre missing the nose off the mona lisa :)

Interesting. I've tried a bit of high pass sharpening on the Ha data that I captured last night and just can't get any payoff...

With short nights and bloomin awful weather I think Martin has done an awesome job to pull a decent image out of the hat.

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Interesting. I've tried a bit of high pass sharpening on the Ha data that I captured last night and just can't get any payoff...

With short nights and bloomin awful weather I think Martin has done an awesome job to pull a decent image out of the hat.

Depends on your method, and how much you are applying. After creating a star layer, I usually apply high pass (to the overlay layer) with a setting of 4 - 5 pixels, then play about with the opacity to get an idea of what looks best before flattening the image.

Buy yes, for this time of year he's done well to get that much data. Im more or less in shutdown mode until the middle of July, hopefully a few clear nights will co-incide with my annual leave... hah! yea right! :D

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Hi Martin I'm no AP but I love looking it what you guys do I think the pics you all put up are amazing so all I can say is I think that's a great image I'd love to be able to do something like that who knows may one day

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Depends on your method, and how much you are applying. After creating a star layer, I usually apply high pass (to the overlay layer) with a setting of 4 - 5 pixels, then play about with the opacity to get an idea of what looks best before flattening the image.

Thanks for the reply and the tip. I've been tending to have a high pass layer (blend mode overlay), mask it out completely and then selectively paint back in the bits I want to sharpen, using shades of grey if I want to apply it differentially. I've been pleased with the results on the galaxies that I did this summer, but couldn't get a benefit on this target - maybe I just don't have enough data as the noise introduced by the sharpening seems to drown out the benefit and if I apply a slight Gaussian blur and then sharpen I end up pretty much back where I started...

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Thanks for the reply and the tip. I've been tending to have a high pass layer (blend mode overlay), mask it out completely and then selectively paint back in the bits I want to sharpen, using shades of grey if I want to apply it differentially. I've been pleased with the results on the galaxies that I did this summer, but couldn't get a benefit on this target - maybe I just don't have enough data as the noise introduced by the sharpening seems to drown out the benefit and if I apply a slight Gaussian blur and then sharpen I end up pretty much back where I started...

No prob :)

But yes, it does help if you have a lot of luminance data (L or Ha) otherwise the process may introduce noise into some areas of the image. I hadnt thought about selectively adding high pass before (apart from experimentation with layer masks), my usual method is noels "select brighter stars", ctrl+J, then create a copy of the background layer (blend mode overlay), then work from there.

There are some targets where this will not work well, most noteably M33 or the Cocoon nebula. Anything with a really diffuse structure or dense starfields dont respond well to high pass in my experience.

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There's maybe rather more NR than I'd use myself but I don't find it upsetting. I don't do pure NB imaging so I'm not a competent critic on the colour but I think it looks pretty good and informative. It's green NB images that I find impossible to digest!

Olly

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Thanks for the comments from everybody. Maybe I should have pointed out that in my Photoshop image, this part of the Elephant trunk was literally the size of a postage stamp, I cropped out just the trunk and then expanded it considerably, and then showed this at max size from the Flickr link - so it's pushing the limits a bit!

Martin

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That's amazing Martin and just goes to show how great your equipment is :) I think the processing is good too - that's a beautiful image and I love it :)

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Thanks for the comments from everybody. Maybe I should have pointed out that in my Photoshop image, this part of the Elephant trunk was literally the size of a postage stamp, I cropped out just the trunk and then expanded it considerably, and then showed this at max size from the Flickr link - so it's pushing the limits a bit!

Martin

This is an important point which imagers will understand more than non-imagers. For me it's a matter of professional pride to get all images to be acceptable at full size. This is a bit silly on my part because there is a lot to be said for capturing at one resolution and then downsizing a bit. (But it upsets me!)

This thread has also raised questions about how we respond to posted images. Nobody has responded with hostility to this image (nor should they, because it is a good image) but, hey, if someone sees too much NR then surely they should say so? You might be surprised to read the hammering that many of my images get over in Europe (or you might not :grin:.) The hammering isn't generally hostile, it's constructive, and I get lots of publications, but I don't get an easy ride, nor do I want one. The truth is that I get a hard time, far harder than here.

Olly

Edited by ollypenrice
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