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Sh2-155 (Cave Nebula) in HST


swag72
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The data collection was the easy part in this image - As per usual, no subs dropped and faultless 30 minute subs. The processing was a little tricky though. I had to crop some off the bottom as I'd stupidly messed up the alignment last night - and there's a difference in sub numbers because of some high level cloud.

I really would welcome some thoughts on this - It was a difficult one to process and I'm not totally sure about it.

Details:

M: Avalon Linear fast Reverse

T: Takahashi FSQ85 0.73x

C: QSI690-wsg with 3nm NB filters

14x1800s Ha

15x1800s OIII

13x1800s SII                  Total integration time 21 hours

post-5681-0-64321300-1407168701_thumb.jp

You can see a larger version here http://swagastro.weebly.com/uploads/2/3/3/7/23377322/sh2-155.jpg

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Lovely image once again Sara: plenty of dark dusty molecular clouds to entice the eye and draw it into the centre of the image.

Those 3nm filters really bring contrast . . . I'd better get saving, more people seem to be moving to them from Baader.

Barry

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Looks excellent as usual Sara, no need to question your processing! I think we all doubt how our images look because we stare at them for so long during post and get to see the knitty gritty stuff behind the curtain.

The only thing i could suggest is to see a slightly darker version just to compare, but thats just my personal taste speaking. Other than that dont change a thing!

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That is a stunner Sara.  I love the way that colour rendition brings out the dust.  Did the OIII or SII bring out any extra detail and did you add that into the luminence?  I always um and ah about how much OIII and SII data to collect (esp SII). 

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Cracking job Sara, this is a subject I keep coming back to but I've never even considered doing it in NB.  You have literally shown it in a new light, really vibrant and fresh.  It could stand more data perhaps to smooth things out a bit but I would be chuffed to bits if it were mine, btw your link to a larger image doesn't work for me.

Mike

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Thanks all for your comments - Much appreciated.

@iksose - I did start off with a darker version, but found that I preferred this one. The darker one just seemed to hide too much nebulosity.

@Martin - I used some Ha for the luminance, and also later in the processing I created a false luminance of the whole image and added that. The SII was stronger than the OIII in this one.

@Mike - I agree that it is a little noisier than I would have liked, but I just wanted to move on!!! The link works for me btw.

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I think it looks great and I like the colors. You are right about the difficulty in processing this target. I tried last year and was never really happy but I had to pull the plug and move on.

JB

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Beautiful, just beautiful! Is that a sea horse or a dragon dead centre?!

A tricky one regarding feedback as it does work very well as is. There does seem to be quite a lot of noise, especially in the darker portions. Why is that? Extreme stretching? Might a slightly higher contrast version darken those areas and 'hide' some of that noise? I'm sure all the dusty detail would still shine through as it is sooooo rich!

Loving the Tak!

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Thanks Elio, JB and Gav - It is a bit noisy, which I think is down to probably stretching some of it to within an inch of it's life!!! OIII and SII was woefully small and the Ha was faint.  I decided that a little noise is better than over smooth, so quit while I was ahead!!! Sounds like I'm making excuses now :grin:

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I could just copy and paste the same comment again and again onto you image posts.

Instead, my new anticomments!

Where's the star bloat and halos? Very dissappointed in this image...distinct lack of artifacts and satellite trails as well!

;-D

Sent from my GT-N5110 using Tapatalk

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Where's the star bloat and halos? Very dissappointed in this image...distinct lack of artifacts and satellite trails as well!

;-D

Cheers Neil - I will try to add some next time just for you!!!! That cloud in the North of Spain must be driving you mad :grin:

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Cheers Neil - I will try to add some next time just for you!!!! That cloud in the North of Spain must be driving you mad :grin:

now there was no need for that! [emoji13]

I'm having fun waiting for clear skies, Sunday was clear but lots of moisture in the air.

Sent from my XT1032 using Tapatalk

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Another stunning image. It almost makes me want to take up imaging myself. But I think I will just continue to marvel at the breath- taking photos of you experts and stick to visual obseving.

All the best and thanks for posting your efforts

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